All trouble codes → Engine misfire codes

Engine misfire codes

A misfire means one or more cylinders aren't burning the fuel–air mixture completely. You may feel a shake, a stumble or lost power, and a flashing check-engine light means raw fuel is reaching the catalytic converter — stop driving before it's damaged. Random misfires point at something shared by every cylinder (fuel pressure, a vacuum leak, timing); a single-cylinder code points at that cylinder's coil, plug, injector or compression.

Common causes

• Ignition coil or spark plug
• Fuel injector
• Vacuum leak at that cylinder
• Low compression (valves, rings, head gasket)
• Carbon build-up on intake valves (direct injection engines)

First checks

• Read Mode $06 misfire counts per cylinder to confirm which cylinders
• Swap the coil with a neighbouring cylinder, clear codes and see if the misfire follows
• Inspect plug gap/condition; check injector balance and compression/leak-down if it doesn't follow

System: Ignition system / misfire. This is general guidance for the generic OBD-II codes in this group; always confirm against the service information for your specific vehicle.