GM

A: Ignition coils tend to last around 100,000 miles of driving, although this distance can vary depending on coil quality and driving conditions. Anything that puts the engine under more strain may cause your coils to wear out sooner.

A: Coil Style.
Primary Resistance.
Turns Ratio.
Maximum Voltage.

A: Your car is likely still misfiring because of underlying issues like a faulty fuel injector, vacuum leak, damaged ignition wiring, low compression from a mechanical problem, or even a problem with the engine's computer (PCM) or related sensors. To accurately diagnose the problem, you should scan the Check Engine Light for specific codes, inspect the ignition wiring and coil boots for damage, and consider performing a fuel pressure test or compression test.

A: Symptoms of a failing ignition coil include an illuminated Check Engine Light, engine misfires and rough idling, difficulty starting, poor acceleration, a loss of power, and a noticeable fuel smell from the exhaust, sometimes accompanied by a strong gas odor or black exhaust smoke. A vehicle may also backfire, sputter, or stall when a coil is failing.

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: Yes, a bad ignition coil can definitely cause a rough idle. A failing ignition coil prevents a spark plug from firing correctly, leading to a misfire and a shaky, uneven engine performance when the vehicle is idling. This incomplete combustion can make the engine feel shaky, and the engine RPMs may also become erratic at idle.