Backfires and Afterfires

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

POSSIBLE CAUSE ACTION


EGR open all the time Check EGR system in "Testing Procedures" in Emissions

Leaking EGR gasket

Air management valves Check Air Injection system in "Testing Procedures" in Emissions

Deceleration valve Check valves for proper function.