Backfires

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 (MPI only).


EGR malfunction ^ Check EGR system.