The engine computer sees misfires on more than one cylinder or with no fixed pattern. The driver usually notices rough idle, shaking and weak acceleration, and the engine light may flash.
Likely causes, most common first
- Worn spark plugs or coils
- Vacuum leak or unmetered air
- Low fuel pressure or dirty injectors
- Low compression
Parts usually involved
- Spark plugs
- Ignition coils
- Fuel injectors
- Intake gaskets
Test before you replace
Read the misfire counters and fuel trims, then check for vacuum leaks and fuel pressure before replacing ignition parts.
General guidance for generic OBD2 codes. Always follow the maker's procedure for the car in front of you.