VOLKSWAGEN

A: Misfiring spark plugs.
Rough idling and stalls.
Weaker engine power.
Lessened gas mileage.
Black exhaust smoke.
Slow-to-start engine.
Blinking check engine light.

A: Ignition coils typically last upwards of 100,000 miles. Actual mileage will vary based on your vehicle and driving habits, but regular maintenance of ignition system components can help maximize the life of your coils.

A: You generally do not need to replace ignition coils with spark plugs, as spark plugs are maintenance items that wear out, while coils typically only need to be replaced when they fail and cause engine misfires. However, replacing spark plugs at the same time is a convenient good idea if access is difficult, as it avoids doing the labor twice.

A: You can drive with a bad ignition coil, but it is not recommended for more than a short distance to get to a repair shop, as it can lead to severe and costly damage to your engine, catalytic converter, and potentially other components. Driving with a misfiring cylinder can cause unburned fuel to enter the exhaust, damaging the catalytic converter, diluting the engine oil, and causing premature wear on the cylinder walls and bearings.

A: Replacing an ignition coil's difficulty varies significantly by vehicle, ranging from a 10-minute, easy task for many modern cars to a multi-hour job requiring extensive engine disassembly for others. Difficulty is often determined by accessibility, as some coils are easily reached on top of the engine, while others are hidden behind components like intake manifolds.

A: To check if an ignition coil is bad, listen for engine misfires and look for a blinking check engine light, then use a test light to check for spark at the spark plug or test the coil's resistance with a multimeter, or swap coils to see if a misfire follows a specific coil.