Backfires

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

^ Check for loose wiring connector or air duct at Mass Air Flow (MAF) Sensor.

^ Perform a compression check - look for sticking or leaking valves.

^ Check EGR operation for being open all the time. See CHART C-7 or C-7A.

^ Check for faulty or loose fit of EGR gasket.

^ Check for proper valve timing.

^ Check output voltage of ignition coil.

^ Check for crossfire between spark plugs (distributor cap, spark plug wires, and proper routing of plug wires).

^ Check for intermittent condition in ignition system.

^ Check engine timing - see Emission Control Information label.

^ Check for faulty spark plugs and/or plug wires or boots.

^ Check deceleration valve (manual transmission).