• The brake pedal vibrates during braking.

Common cause: Rear misalignment - If you only feel the vibration through the pedal itself, the vibration is isolated to the rear of the vehicle. This usually happens because the rear brake shoes and drums become misaligned and cease to make the even contact necessary for smooth braking. The most common causes of misalignment is the gradual warping of the rear drums, although the wheel bearings coming loose will produce the same effect. The drums must be machined to eliminate the warpage, and the shoes should be replaced as well for lack of proper alignment with the drums after the machining process.

Common cause: Front misalignment - however, if there is also a vibration in the front end of the vehicle in addition to the vibration through the pedal, then it is likely that the front pads are not aligned properly with the pads. The result is that the disc and pad cease to make the even contact necessary for smooth braking. The most common causes of misalignment is the gradual warping of the disc, although the wheel bearings coming loose will produce the same effect. The discs must be machined to eliminate the warpage, and the pads should be replaced as well for lack of proper alignment with the discs after the machining process.

• When I apply the brakes, one wheel locks up.

Common cause: When only one wheel locks up, it means that the other wheel is not gripping the pavement well. This imbalance causes wheel that is gripping the road properly to more quickly reach the point of skidding. So when only one wheel locks up, start by checking the opposite side's brake linings for dirt/contamination. Do not drive the vehicle until the situation is resolved.

• When I release the brake pedal, one of the front brakes remains applied.

Common cause: Caliper and caliper piston - your disc brakes use the caliper to push the brake pads up against the disc, slowing the vehicle. If the caliper's support bracket becomes corroded, it will prevent the free movement of the caliper that is essential to the operation of the brakes. If the caliper sticks temporarily in the closed position, the affected brake will drag. This is an easy fix since you merely have to clean the bracket with a wire brush and apply lubricant.

The caliper is activated by an internal piston that hydraulically squeezes the caliper closed. A faulty piston will sieze and cause the caliper to essentially lock into the closed position.

• When I release the brake pedal, one of the rear brakes remains applied (rear disc brakes).

Common cause: Caliper and caliper piston - your disc brakes use the caliper to push the brake pads up against the disc, slowing the vehicle. If the caliper's support bracket becomes corroded, it will prevent the free movement of the caliper that is essential to the operation of the brakes. If the caliper sticks temporarily in the closed position, the affected brake will drag. This is an easy fix since you merely have to clean the bracket with a wire brush and apply lubricant.

The caliper is activated by an internal piston that hydraulically squeezes the caliper closed. A faulty piston will sieze and cause the caliper to essentially lock into the closed position.

• When I release the brake pedal, one of the rear brakes remains applied (rear drum brakes).

Common cause: Cylinder piston - when depressed, these pistons push the brake "shoes" against the brake drum to create stopping friction. A faulty piston will sieze and and cause the affected brake to lock and drag.

Common cause: Retracting springs - when you release your brake pedal, the brake shoes are pulled away from the brake drum by springs. Broken or overworn springs will leave the shoes pressed against the drum, locking the brake in the closed position. If the springs look fine, the cylinder piston is likely the culprit.

• When I release the brake pedal, all of my brakes remain applied.

Common cause: Master cylinder - this component supplies hydraulic pressure to all of the brakes. As the master cylinder begins to malfunction, it cannot properly scale the hydraulic pressure back down after the brake pedal has been depressed and released. This results in all four brakes remaining in the closed position.

Common cause: Binding brake pedal - check the area surrounding the brake pedal for any objects that may impede the pedal's movement. When the pedal "binds" or is unable to return from a depressed position to a fully released position, all of your wheels will lock.

• The front of the vehicle makes a clicking sound during braking.

Common cause: Front disc brakes - it is common for the bracket which holds the brake caliper in place to work itself loose over time. Then when the brakes are applied, the bracket clicks as the caliper squeezes the brake pads against the disc.

• The front of the vehicle makes a clunking sound during braking.

Common cause: Front suspension - during braking, the weight distribution across the vehicle's chassis shifts hard to the front of the vehicle. Front suspension components that are ready to be replaced will often emit a resounding "thunk" during this lurch forward. The first likely component to check is the ball joints.

• My brakes are creating a rattling sound.

Common cause: This is usually the result of one or more loose brake parts. In disc brakes, the caliper mounting bolts, are the likely source of the noise. These hold the caliper secure to the its mounting bracket, and it is common for them to work themselves loose over an extended period of time. In drum brakes, common culprits are the retaining springs and the return springs. The retaining springs are the ones holding the brake shoes in the proper position; the return springs pull the shoes back when the brakes are released.

• I can push the brake pedal much closer to the floor than I used to.

Common cause: Check the brake fluid level. Observe the level without removing the reservoir cap if possible, by leaning on or rocking the vehicle gently.

Common cause: Brake linings - when these become worn down to the point of near-uselessness, they will allow the pedal to travel farther during braking.

• I can push the brake pedal all the way to the floor without much effort.

Common cause: You have lost brake fluid pressure, so there is nothing to stop the pedal from going to the floor. Your braking system's "master cylinder" may be leaking brake fluid. This is common and happens when the seal around the master cylinder's primary piston manfunctions, allowing brake fluid to enter behind the piston and causing the brake pedal to sink even under light application of pressure.

• The vehicle pulls to the right or left when I apply the brakes.

Common cause: The front end controls the steering of the vehicle, so we are concerned with the front tires, brakes, and suspension. Check the front tires to ensure that the tire pressure is the same on both sides. If they are not matched, the vehicle will pull towards the side with lower tire pressure. Remove the front wheels one side at a time, and inspect the brake discs. You are looking for an greasy substance that may not be clearly visible. Check by touching the discs with your finger as well (do not do this immediately after driving the vehicle as the discs will be hot.) If you discover an oily substance, then you have a contaminated disc that is affecting your braking performance on that side only. If the other side is still functioning properly, the braking is uneven and the vehicle will veer to one side when the brake pedal is applied. The oily substance that contaminated the disc came from a leak, most likely in the brake line or the caliper.

• The brake pedal feels spongy during use.

Common cause: A brake pedal normally feels solid during use because it is pushing brake fluid through the brake lines, and brake fluid does not compress under the pressure that is forcing it through the system. However, if air gets into the brake lines, the pedal will feel spongy, since the air will compress under the pressure as you brake.

Unless you recently had your vehicle worked on, in which case the technician may have forgotten to bleed the air from the brake system, it is likely that you have a leak in the brake system where air is being allowed to enter.

• It takes more pressure on the brake pedal than usual to slow or stop the vehicle.

Common cause: Power brake unit - a vacuum hose connects the engine to a "power brake canister" found between the firewall and the master cylinder. The problem may be the canister itself, or may simply be a leaking vacuum hose.

• My brakes are squealing.

Common cause: Pad wear sensor - when the brake pads are near being worn out, this thin piece of metal connected to the pad makes contact with the brake disc, producing a squealing noise designed to inform you that it's almost time for a new set of pads.

Common cause: If you are using cheap non-factory replacement brake pads, that alone can cause squealing. You may want to try a different brand of brake pad.

Common cause: Brake pad vibration - a slightly loose caliper or brake pad can cause a high-frequency vibration, producing an intermittent squeal. Remove the wheel to check for loose components and tighten as necessary. Check peripheral brake components such as the anti-rattle springs for looseness. This type of vibration can also be caused, in the case of disc brakes, when a disc that has become "scored" or deeply grooved makes contact with the brake pad.

• My brakes are grinding.

Common cause: Brake linings - when these become worn down to the underlying metal, they will go from a "squeal" to a shrieking, grinding noise due to the metal on metal friction created by applying the brakes. At this point not only are the brake linings used up, but the brake discs or drums will have to be machined down to smoothness again due to the damage from grinding against metal. You may even have to replace the disc/drum depending on the extent of the damage.

• The vehicle shakes abruptly during braking.

Common cause: This usually happens because the rear brake shoes and drums become misaligned and cease to make the even contact necessary for smooth braking. The most common causes of misalignment is the gradual warping of the rear drums, although the wheel bearings coming loose will produce the same effect. The drums must be machined to eliminate the warpage, and the shoes should be replaced as well for lack of proper alignment with the drums after the machining process.

• The vehicle feels reluctant to pull out of turns.

Common cause: Your alignment is off, meaning that your wheels are no longer all at the precise angle that is optimal for your vehicle. The wheels are no longer straight relative to the vehicle's frame. This is the most common source of this particular problem. You will not be able to perform an alignment without shop equipment.

Common cause: A steering component is binding.

• The steering wheel vibrates at certain speeds.

Common cause: Check your front tie rods and ball joints for a loose suspension part. At speed these parts can create a monster vibration if one gets even a little bit loose.

Common cause: A wheel has become imbalanced, meaning that the weight distribution is no longer even throughout the wheel. When you get the wheel spinning, the heavy spots cause the wheel to wobble or rotate unevenly. You can feel the effect transmitted through the steering linkage right up into the steering wheel. An imbalanced wheel can be caused the wheel itself, or by the actual tire wearing unevenly.

• The steering wheel feels as if it is coming loose.

Common cause: Steering column bracket - this piece is responsible for securing the steering column into position. This is a cheap fix.

Common cause: The universal joint connects the steering gear to the steering shaft, inside the steering column.

Please attend to this problem quickly because in short order your vehicle may become unsafe to drive.

• Steering has become stiff over time.

Common cause: Make sure that your tires are inflated to the proper tire pressure, especially the front tires.

Common cause: Power steering (vehicles with power steering systems only) - the power steering pump applies hydraulic pressure to the steering gear. If the pump fails over an extended period of time, you will experience a gradual increase in stiffness during turns. Another likely cause within the power steering system is a leak of the hydraulic fluid used to create pressure and make turning the wheel easier. Check the power steering fluid level and top it off if needed.

• Steering becomes stiff temporarily during driving.

Common cause: Power steering pump - either the pump is failing, or the power steering belt is slipping (often caused by wetness). Check the belt before you spend any money on a new pump. Driving with a malfunctioning power steering pump is not safe.

• My car constantly wants to pull left or right during driving.

Common cause: Your alignment is off, meaning that your wheels are no longer all at the precise angle that is optimal for your vehicle. The wheels are no longer straight relative to the vehicle's frame. This is the most common source of this particular problem. You will not be able to perform an alignment without shop equipment.

Common cause: You may have a "dragging" brake on one side, or a brake that is not fully releasing when you release the brake pedal. Drive the vehicle for approximately twenty minutes, then jump out and quickly touch each each of your front hubcabs to see if one is hotter than the other. If so, the hot wheel is generating the friction that is pulling the vehicle to one side. Hopefully the problem is only a support bracket that has corroded and is causing the brake to drag. You can simply clean the bracket off with a wire brush and apply lubricant. If no corrosion is present the next most likely culprit is the caliper.

Common cause: Check your tire pressure and fill all tires to the proper pressure level. If the front tires are two different pressures that is the likely cause of the problem. The vehicle will pull towards the side with the lower tire pressure.

• Tires make a screeching noise when turning a corner.

Common cause: The most likely cause is improper tire pressure in one or more wheels.

Common cause: Steering angle - this is related to your alignment in that your vehicle's wheels are supposed to keep to a certain angle relative to their connecting parts during turns, or the result is a screech from the tires as they create drag. You need an alignment. Get one as soon as possible since the misalignment causes your tires to wear faster than normal.

• I hear a clicking noise from the front end of the vehicle during turns.

Common cause: CV Joint (front wheel drive vehicles only) - the flexible joint that allows engine power to be smoothly applies to the wheels by absorbing minor surges. When the joint becomes worn it will begin making noises, and during turns the noise will be a click. Crawl under the vehicle and look for the ribbed rubber "boot" that houses the CV joint. If the boot is torn, that is a telltale sign that dirt and mud have entered and ruined the joint, causing the clicking noise you are hearing.

Common cause: A worn or damaged front end component can bind and begin to make clicking noises. The stress on these components is more intense during turns than during straight-line driving, and as such you are more likely to hear clicks while turning. Components to check are the control arm bushing, steering knuckle, tie rod end, and ball joint. Clicking sounds are almost always a sign of more serious problems to come.

• Steering feels sloppy, especially during turns and at speed.

Common cause: If your tires are overinflated, they don't grip the road properly. Instead of "hugging" the road, they will "bounce" or roll unevenly. As you increase in speed, the instability of the pulsating wheels will become more intense and you will feel the sloppiness of the steering increase.

Common cause: Your front end components wear out over time and the result is loose steering. Take a look at the underside of your vehicle's front end and see if any of the metal parts appear particularly worn or asymmetric (make sure the wheels are straigtened out first.) Steering problems are extremely hazardous to ignore, so if you are experiencing problems do not drive the vehicle.

• My tires are wearing in an unusual or uneven fashion.

Common cause: Overinflation - wear in the middle of the tread area of the tire.

Common cause: Underinflation - wear on the outer edges of the tire but not in the middle of the tire.

Common cause: Wheel imbalance - wear at seemingly random spots on the tire.

Common cause: Misalignment - wear on either the outer edge only or the inner edge only.

• The ride is stiff and bumpy.

Common cause: Overinflated tires reduce the tires' ability to absorb the shock of bumps in the road. Let some of the air out if your tire pressure measures too high and you will regain some cushiness.

Common cause: If the ride is extremely stiff you may have a siezed shock absorber. If you must swab out a shock or strut cartridge you need to do both sides of the vehicle together. You can do the front seperately from the rear, however.

• The ride is overly soft and bouncy.

Common cause: Your vehicle's shocks are designed to restrict the movement of the suspension springs that your vehicle "floats" upon. When a shock becomes worn or damaged and can no longer control the springs, the ride will become noticably bouncy and handling will suffer dramatically. Determine whether the issue is the front end or the rear end and replace only those shocks to begin with.

• I hear a loud thump from under the vehicle whenever I drive quickly over a bump or dip.

Common cause: It is likely that the shocks or strut cartridges are worn and in need of replacement. To do a quick test, stand in front of the vehicle and push down rhythmically to get the vehicle "bouncing". When you let go of the bumper, it should only bounce one time if the components are working properly. After you check the front of the vehicle, repeat the process in the rear.

When you hit a bump or a dip in the road, the vehicle's weight comes down hard on the suspension components and if a component is weak or worn it will not be able to handle the extra burden. Since suspension pieces work on a principle of expanding and contracting to absorb an impact, a weakened suspension piece will be easily bottomed out. This means the component is compressed to its limit and can not move any farther to absorb impact from the road. When this happens you will hear the signature "thump" of a suspension component bottoming out.

• The entire vehicle vibrates when driving at certain speeds.

Common cause: This kind of pulsation is usually the result of one or more wheels rotating unnaturally, and consequently rolling unevenly. If the weight of your wheel is not distributed evenly, or if by defect the rim or tire is not perfectly round, the awkward rolling motion will cause vibration that can be felt through the steering wheel or passenger compartment floorboards, especially at certain speeds.

• The front of the vehicle vibrates at certain speeds.

Common cause: One or both of the front wheels is out of balance.

• The rear wheel of the vehicle vibrates at certain speeds.

Common cause: One or both of the rear wheels is out of balance.

• Airflow through my vents has weakened.

Common cause: One or more of the air doors inside the ducts may be stuck in a partially closed position. The ducts may be blocked by matter building up as it enters the fresh-air intake port. The port is located near the bottom of the windshield, on the vehicle's exterior. You may need to open the hood.

• No air comes through my vents.

Common cause: You are likely experiencing a blower motor failure. You may be able to simply swap out the fuse if it has blown, for a simple quick fix. Locate your vehicle's fusebox and pinpoint the blower's fuse. It will be labeled "a/c" or "heater". If replacing the fuse solves the problem temporarily, but soon afterwards the new fuse fails, then you have a short somewhere in the electrical system and you need to see a specialist.

• I have the proper airflow but the heater doesn't seem to be warming the air.

Common cause: For vehicles with fully manual (standard) heating systems -

Your heater produces warmth because the engine circulates hot coolant through it. The entrance to the heater's core, where the coolant is circulated, is guarded by a valve. A faulty heater control valve prevents the hot coolant from doing its job, and the air from your vents will not be warmed. This is most likely the cause of your problem.

The heater core looks a lot like a miniature radiator. It is usually located behind the vents on the dashboard.

If the valve itself is not malfunctioning, the heater component that activates the valve could be the problem.

If you allow a technician to perform this repair, you should insist on replacing the valve only, to see if that resolves the issue, before going on with the full heater core replacement.

Common cause: For vehicles with automatic temperature control -

Your vehicle's computer monitors the passenger compartment's temperature and adjusts the temperature of the airflow into the compartment to maintain a target comfort level temperature. A rudder-like door called the "blend door" combines hot air with cold air to create the proper airflow temperature into the compartment. If this door becomes even partially stuck in one position, the vehicle's automatic temperature control will no longer be able to perform properly.

A more likely cause of the problem is the "ambient air sensor" which monitors the passenger compartment's temperature. If this sensor begins feeding inacurrate information, or no information at all, to the temperature control computer, automatic temperature control can not function.

• My air conditioner emits a mildew smell through the vents.

Common cause: Your air conditioner produces condensation during operation. The moisture escapes the air conditioner's evaporator unit (where the air is cooled) by dripping down into a "drain pan". From there it makes head down towards the street through a hose.

If the drain pan becomes clogged, the moisture that is trapped will generate mildew.

From under the vehicle, locate the drain hose and clean any debris from its end. If this end isn't clogged, seek the help of a professional to locate the blockage. Allow a couple of days after un-clogging the drain pan for the smell to disappear.

• My air conditioner functions most of the time, but sometimes produces warm air.

Common cause: Your A/C compressor will automatically disengage in times of engine stress or excess heat. The compressor is a burden on the engine so when the engine reaches its limits it will automatically divert power from the air conditioner system. This is completely normal.

Common cause: If the pattern of warm air coming from the A/C is random and infrequent, there could be an electrical problem causing the A/C to blow warm air. A broken ciruit due to a wire that has lost contact is common. The effect is temporary because the loose wire will often remake contact it is supposed to be connected to, resuming the circuit and producing cold air until the wire is shaken loose again.

Common cause: Another potential culprit is the core of the A/C unit, the "compressor", which circulates refrigerant through the A/C system. A faulty compressor can function sporadically, causing the A/C to blow warm air during down periods.

Common cause: The A/C "expansion valve" guards the entrance to the core of the A/C, which is called the "evaporator". The symptom of a faulty expansion valve is that the A/C will work fine for awhile each time the engine is operated, but if the engine runs for an extended time the air flow turns warm. The A/C expansion valve controls the amount of refrigerant that enters the system. Moisture can enter the A/C system through tiny leaks, and over a period of time as the engine runs and the evaporator gets colder, the moisture that has collected in the expansion valve can freeze. The blockage prevents refrigerant from entering the evaporator, and consequently the dashboard vents begin to yield warm air. You will need a professional technician to locate any leaks in the system, and to "charge" your system by refilling the refrigerant after making repairs.

• My air conditioner no longer cools the air coming through the vents.

Common cause: A refrigerant leak is the likely culprit. A hose or seal can rupture and drain off the refrigerant necessary to cool the passenger compartment. The effect will be sudden.

Common cause: Another possible cause in cases of a sudden reduction in perfomance is the compressor belt, which may have broken or slipped from its track.

Common cause: If performance is lacking but the reduction was not sudden -

Refrigerant leaks in a hose or a seal can be small enough to make the reduction in performance almost too gradual to notice at first. The leaks will not stay small for long, unfortunately. See an A/C specialist.

• The radiator boils over when the engine is not overheating but is only semi-hot.

Common cause: You may have the wrong mixture of anti-freeze and water in your cooling system. This will cause the water to boil at a much lower temperature than normal. Replace your coolant with a 50/50 mix after having the system backflushed to wash out the old coolant.

Common cause: You may solve the problem by replacing the radiator cap. If the radiator cap is not sealing properly with the fill hole, it will not keep the cooling system under the proper pressure. Without this pressure the coolant's boiling point is lowered below the usual mark, causing the radiator to boil over when the engine is not overheating. Check for any cracks in the rubber underside of the cap, and check the fit of the cap to the radiator's fill hole.

• My temperature guage consistently reads hot very shortly after I start the engine.

Common cause: A low coolant level is the easiest problem to fix. Remove the radiator cap (on a cold engine only) and check that the coolant level is sufficient.

Common cause: You may have a faulty water pump. Since the water pump circulates the coolant through the radiator, a malfunction will quickly cause excess heat.

Common cause: Your vehicle's thermostat is designed to keep the coolant from the radiator when it is not needed, as in when starting a cold engine. The thermostat can stick in this "closed" position, causing the engine to become hot shortly after starting.

Common cause: Check your radiator hoses while another person starts the engine for you. Watch the hoses as the engine heats to operating temperature. Specifically, look for a hose that appears to collapse in upon itself a little bit. This is common with old hoses, but can be the result of a defective hose as well. The coolant's cycle of flowing through the engine is interrupted and the trapped coolant heats up quickly.

• My vehicle overheats in hot weather.

Common cause: A low coolant level is the easiest problem to fix. Remove the radiator cap (on a cold engine only) and check that the coolant level is sufficient.

Common cause: Clogged radiator. If the air hitting the radiator is not getting through to cool the coolant, the vehicle will overheat in hot weather at any speed of driving. Clean the exterior of the radiator, removing dirt and debris with hot water. Purchase a backflush kit and perform a backflush to help restore radiator efficiency.

• The vehicle overheats when not moving or in slow traffic.

Common cause: Vehicles without electric fan -

The most likely cause is a broken or slipping fan belt. Press down on the middle of the belt to check for tightness - a properly functioning belt will only move about one half of an inch. Tighten the belt if it is overly loose.

The "fan clutch" activates the fan in times of extreme engine heat. A clutch malfunction can completely disengage the fan and cause overheating.

Common cause: Vehicles with electric fan -

The most likely cause is the fan switch. This is a common component to have to swap out on a middle-aged vehicle.

The coolant sensor monitors the temperature of the coolant and activates the fan when the coolant is too warm. A faulty sensor means the fan will not dissipate excess engine heat properly.

• Battery light comes on during driving.

Common cause: If the battery is in order, this generally points to a problem with the alternator. Your alternator charges the battery while powering vehicle accessories like the ignition and air conditioner. If the alternator stops supplying enough power to these componenets during vehicle operation, they will begin to draw on the battery itself.

The first thing to check is whether the alternator belt is in place and functioning properly. If the belt doesn't need replacing, you are looking at a new or rebuilt alternator to resolve the issue.

• Oil light comes on during driving.

Common cause: Check the oil level and top it off it is low. Be careful not to overfill.

Common cause: The oil pressure sensor will activate the oil light if it detects a drop in oil pressure. If the sensor malfunctions, it can send a false positive to the oil light when in reality the oil pressure is stable. If the sensor proves not to be the problem, you may have a loose wiring connection between the oil warning light and the oil pressure sensor.

Common cause: The oil pump is the source of oil pressure throughout the engine. If the pump falters or stop working entirely the oil light will come on.

If you continue to drive the vehicle in this condition, there is a good chance that you will permanently damage your engine.

Common cause: If the oil light only comes on when the engine is heated up, it is possible that you are using the wrong viscosity (or thickness) of oil. When the engine reaches high temperatures and heats the oil, the oil becomes thin and oil pressure drops. The thicker the oil in your engine, the more resistant to extreme engine conditions. The same problem occurs when oil is contaminated over time by dirt.

Common cause: If the oil light only comes on briefly when the engine is idling, changing the oil and replacing the oil pan screen may prove an efficient quick fix.

• Brake light comes on during driving.

Common cause: Hydraulic system - a pressure imbalance will activate the brake warning light. Check the master cylinder for leaks and examine the brake lines carefully. If you can't find the problem, tow the vehicle to a shop; do not drive it.

Common cause: The brake fluid level is low. This is especially likely if the light only flickers rather than staying on. Pop the hood and find the brake fluid reservoir on top of or near the master cylinder. Check the fluid level without removing the reservoir cap if possible, by leaning on or rocking the vehicle slightly.

• Vehicle doesn't start and there is a grinding sound.

Common cause: The starter drive and the ring gear are the most likely culprits. This type of repair is best left to a professional. It may be easier to replace the starter entirely - and you can save money by installing a rebuilt starter.

• Vehicle doesn't start when the engine is very cold.

Common cause: Occasionally a battery will become very weak in extreme outdoor cold conditions. This is usually temporary but you will not be able to crank the engine in the meantime. You may want to upgrade to a better battery that is rated to function properly in extreme cold.

• Vehicle doesn't start when the engine is already hot.

Common cause: Solenoid - this is a switch that turns on the starter when you hit the ignition. Extreme engine heat can cause the solenoid to fail and the engine will not start. You may need to install a solenoid heat shield if the problem persists.

Common cause: Engine oil thickness - if you are using a heavy single weight engine oil, please be aware that in cold temperatures this oil can become thick enough to create friction as you try to crank the engine.

• Vehicle doesn't start and makes no sound.

Common cause: Either the battery is too weak to start the engine, of the solenoid (switch) that activates the starter is malfunctioning.

• Vehicle doesn't start and the engine backfires.

Common cause: Distributor cap - Distributor cap - A faulty distributor cap will cause a misfire, resulting in a severe fluctuation of power from the engine. This happens either when the distributor cap is over-worn, or on particularly wet days when moisture may gather in the distributor cap.

You may be able to remedy the problem simply by drying the underside of the cap with a rag.

Common cause: Timing belt - the timing belt is usually located under the hood behind a plastic shield called the timing belt cover. Check the timing belt to see that it is in place and not dramatically loose.

• Vehicle doesn't start and the engine turns over quickly.

Common cause: Air filter - remove the filter and inspect it carefully. If there is an excess of dirt covering the filter, it is possible that the buildup is blocking the air flow into the engine. Not enough air is present for combustion and the engine is unable to start. Clean the filter by tapping it firmly against the ground for a possible temporary fix, but replace the filter as soon as possible if it is severely clogged.

Common cause: Timing belt - when this breaks or malfunctions, the engine loses compression and can not start. The timing belt is responsible for controlling the opening and closing of each valve in the order of the combustion sequence.

• Vehicle doesn't start and the engine turns over slowly.

Common cause: Battery - you can check the battery at night by turning on the lights without the engine running, and then cranking the engine up. If the lights dim significantly or go out entirely as the engine cranks, there is a problem with the battery. Open the hood and check the battery terminals for dirt/grime buildup. If none is present then you probably have a weak battery.

Common cause: Battery elecrolyte - if the problem occurs during extreme cold outdoor temperatures, the electolyte inside your battery may have frozen partially. The battery will lack the power to crank the engine.

Common cause: Electrical connections - check the lines from the battery to the starter for loose connections.

Common cause: Starter - If you noticed a grinding sound coming from under the hood as the engine was cranking, it is likely the starter is bad and can't crank the engine fast enough to start it. You may be able to save money by replacing it with a rebuild starter as opposed to a new one.

• Vehicle doesn't start and the engine sputters.

Common cause: Distributor cap - A faulty distributor cap will cause a misfire, resulting in a severe fluctuation of power from the engine. This happens either when the distributor cap is over-worn, or on particularly wet days when moisture may gather in the distributor cap.

You may be able to remedy the problem simply by drying the underside of the cap with a rag.

Common cause: Timing belt - The timing belt is usually located under the hood behind a plastic shield called the timing belt cover. Check the timing belt to see that it is in place and not dramatically loose.

Common cause: Spark plugs - pull off the spark plug wires one at a time and check to see that they are all in working order. Reconnect each wire to the plug before moving on to the next for testing. To test a wire, set the free end right next to a clean metal surface and move back a step. Have another person crank the engine while you watch the end of the wire for a spark to arc towards the ground. If one or more of the wires does not create a spark, either the wire is fried or the coil that feeds current to the spark plug is not functioning properly.

• The vehicle starts briefly but does not stay running.

Common cause: Choke (carbureted vehicles) - If you can keep the vehicle running by keeping your foot on the pedal, but releasing the pedal completely causes the engine to stall, the problem is you choke. If you allow a technician to perform the repair for you, he will probably want to replace the entire carburetor, since often the choke is not sold separately. NOTE: if the problem only occurs during cold outdoor weather, it is likely that the choke has stuck in the open position, preventing the rich air/fuel mixture required during cold weather. Try spraying choke cleaner on the choke linkage for a possible quick fix.

Common cause: Fuel filter (carbureted vehicles) - check to see that the fuel filter is not extremely clogged. A clogged filter will allow enough gas through to start the vehicle, but not enough to stay running.

Common cause: Electronic sensor (fuel injected vehicles) - if a sensor fails, the on-board computer will not be able to recognize the temperature outside and adjust the air/fuel mixture accordingly. During cold weather a sensor failure means that the engine will get a fuel/air mixture intended for normal weather, and the engine will not be able to function. To narrow the problem down to a particular sensor, you will need a technician to use an "engine analyzer" on your vehicle, which will run you around $50 depending on what part of the country you live in.

Common cause: Electric fuel pump (fuel injected vehicles) - if your fuel pump is functioning properly, you will hear a slight "whurring" sound as you start the engine. Open the hood and have someone start the engine for you. If you hear the "whuuur", the fuel pump is working and is probably not the problem.

• The engine sputters as I crank it up, but then starts.

Common cause: Spark plugs - pull off the spark plug wires one at a time and check to see that they are all in working order. Reconnect each wire to the plug before moving on to the next for testing. To test a wire, set the free end right next to a clean metal surface and move back a step. Have another person crank the engine while you watch the end of the wire for a spark to arc towards the ground. If one or more of the wires does not create a spark, either the wire is fried or the coil that feeds current to the spark plug is not functioning properly.

Common cause: Engine valves - if the vehicle also sputters while it is idling, it is likely that the valves in your engine are not functioning properly. You may need an expensive valve job at an engine specialist shop.

• When I start the vehicle, the engine turns over very slowly.

Common cause: Battery - you can check the battery at night by turning on the lights without the engine running, and then cranking the engine up. If the lights dim significantly or go out entirely as the engine cranks, there is a problem with the battery. Open the hood and check the battery terminals for dirt/grime buildup. If none is present then you probably have a weak battery.

Common cause: Battery elecrolyte - if the problem occurs during extreme cold outdoor temperatures, the electolyte inside your battery may have frozen partially. The battery will lack the power to crank the engine.

Common cause: Starter - if you noticed a grinding sound coming from under the hood as the engine was cranking, it is likely the starter is bad and can't crank the engine fast enough to start it. You may be able to save money by replacing it with a rebuild starter as opposed to a new one.

• The engine backfires as I start the vehicle.