Backfires

Symptom: Fuel ignites in the intake manifold, or in exhaust system, making a loud popping noise.

POSSIBLE CAUSE ACTION


Exhaust system leaks ^ Visual inspection


Incorrect Air-Fuel mixture ^ Check fuel pressure.

^ Check Air-Fuel ratio.

^ Check O2 sensor output.

^ Perform injector balance test (SFI only).


EGR malfunction ^ Check EGR system.