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.
Exhaust Gas Recirculation