SUBARU

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: Common Subaru bad coil pack symptoms include an illuminated check engine light, rough idling or engine misfires, poor engine performance, reduced fuel economy, difficulty starting, and a possible gasoline smell. The engine misfire results in inconsistent sparks for combustion, causing shaking and loss of power. A failing coil can also lead to an unaddressed fuel-air mixture, which may cause backfiring and exhaust smoke.

A: Individual coils can range from $50 to $150 each, so the total cost changes if you need to replace just one or all of them. The labor costs for a professional installation also add to the final price.

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. Additionally, an old, worn spark plug can cause its corresponding ignition coil to fail prematurely by making the coil work harder, so replacing old plugs is good for coil longevity.

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: No, you should not drive with a bad ignition coil, as it can lead to costly engine and exhaust system damage, poor fuel economy, and a dangerous breakdown. While your car may still run with one or more malfunctioning coils, you should replace the bad coil immediately to prevent unburned fuel from damaging the catalytic converter and to avoid increased stress on the engine's internal components.