What does an ignition coil do?
The ignition coil turns the car battery's low voltage into the high voltage a spark plug needs to ignite the fuel and air in each cylinder. Many modern engines have one coil for each cylinder, mounted on top of the spark plug.
What are the common signs of a failing ignition coil?
- A rough or shaky idle, especially when the engine is warm.
- The car hesitates or jerks when you accelerate, or feels weak going uphill.
- The check-engine light comes on, or flashes while the engine is misfiring.
- Higher fuel use and a smell of unburnt fuel from the exhaust.
Is it the coil or the spark plug?
Both cause a misfire, so a workshop usually reads the fault code first. It tells you which cylinder is misfiring. The mechanic can then swap that coil with a neighbouring cylinder to see if the misfire follows it. If it does, the coil is at fault. If not, check the spark plug.
Is it safe to keep driving with a misfire?
A flashing check-engine light means the engine is misfiring badly. Unburnt fuel can reach the exhaust and damage the catalytic converter, so have the car checked soon and avoid hard driving until then.
Which coil do I need?
Coils differ by model, generation and engine. Send us your car plate or chassis number and which cylinder is misfiring, and we will match the right coil. Many owners change the spark plugs at the same time, so ask us about both.
