Q: On my previous car I could find the spark plugs by following the spark plug wires. I cannot even see the spark plug wires on my new car. Where are they?

A: Many newer vehicles do not have spark plug wires; they have “coil-on-plug” (COP) ignition systems. By eliminating the spark plug wires, your vehicle has a more reliable ignition system. The coil-on-plug system eliminates the need for high voltage spark plug wires that can cause ignition problems over time. Also, if spark plug wires are not properly routed away from the exhaust manifold, the outer insulation can burn. Look for the ignition coils. On coil-on-plug systems the spark plugs are under the coils.

Q: I have a front wheel drive vehicle with a V6 engine. How do I change the back spark plugs? I don’t even see them. Will I need any special tools?

A: Sometimes you need to take the plastic cover (if so equipped) off the top of the engine to access them. You will need a ratchet, spark plug socket, extension, and a swivel joint or two to maneuver through the tight space. On other vehicles, replacing the spark plugs on a transverse mounted V6 is easier from under the vehicle using an automotive lift.

Q: My mechanic told me that my spark plugs might be fouled. What does this mean and how does a spark plug get fouled?

A: A fouled spark plug has been coated with excessive oil, fuel, or other by-products of combustion such as carbon. These deposits coat the insulator tip of the spark plug. When this happens, the insulator part now acts as a conductor of electricity and will short out the electrical spark. Your engine could have several plugs fouled or just one. Depending on the extent and the number fouled, bad spark plugs can cause the engine to lose power, run rough, overheat, and even not run at all.

Q: What does it mean to gap a spark plug?

A: When you gap a spark plug you set the distance between the electrodes. The side electrode, also called the ground electrode, is the piece that protrudes out and makes an “L” shape. The center electrode is the piece that is in the center of the plug. The distance between the two electrodes has to be exact for the spark to fire correctly; otherwise the engine will not run efficiently. To gap a spark plug insert a wire gap gauge or a flat feeler gauge between the electrodes and adjust to the correct gap distance. The gap distance is usually given in thousandths of an inch. The correct gap distance should be on the EPA sticker in the engine compartment.

Q: What does the acronym VTEC represent? I have seen it describing an engine.

A: VTEC stands for Variable valve Timing and lift Electronic Control. This system allows the engine to optimize its power and torque at different engine speeds (rpm) by variably adjusting the valves. This makes the engine very responsive, but also efficient and lower polluting by burning an extremely precise air-fuel ratio.