Backfires and Afterfires

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

POSSIBLE CAUSE ACTION


EGR open all the time,
leaking gasket. See Exhaust Gas Recirculation System


Mechanical condition Check for:
Camshaft out of time
(belt or chain skipped or incorrectly installed);
Worn camshaft (rounded exhaust lobe);
Burned or incorrectly adjusted valves;
Head gasket burned out
between adjacent cylinders;