For 1990-2009 cars

Checks | Action
--- | ---
DEFINITION: The fuel ignites in the intake manifold, or in the exhaust system, making a loud popping noise.
Preliminary Check |

• | Refer to Diagnostic System Check - Engine Controls .

• | Refer to Symptoms - Engine Controls .

Ignition System Checks |

• | Check for adequate ignition coil voltage with a J 26792 Spark Tester or equivalent. Refer to Electronic Ignition (EI) System Diagnosis .

• | Check for damaged or worn spark plugs. Refer to Spark Plug Inspection .

• | Check for the correct ignition timing. Refer to Ignition System Timing Adjustment .

• | Check for crossfiring between cylinders. Check for the correct routing of the ignition coil electrical connectors.

Engine Mechanical Checks |

• | Check for any of the following engine mechanical problems:

- | Incorrect valve lash

- | Broken or weak valve springs

- | Low compression. Refer to Engine Compression Test in Engine Mechanical.

- | Sticking or leaking valves

- | Incorrect valve timing

- | Worn or incorrect camshaft

• | Refer to Symptoms - Engine Mechanical in Engine Mechanical.

• | Check the intake and exhaust system for casting flash or other restrictions.

Additional Checks |

• | Check for the proper fuel pressure. Refer to Fuel System Diagnosis .

• | Verify the PCM grounds are clean, tight, and in the proper locations. Refer to Engine Controls Schematics .

• | Check the Service Bulletins for any updates or information.