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 Air-Fuel ratio, O2 sensor, perform injector balance test, inspect regulator operation (check vacuum line and return hose), check fuel pressure

EGR malfunction Check EGR system, Exhaust Gas Recirculation