GM Service Manual Online
For 1990-2009 cars only

Definition: A mild to severe ping, usually worse under acceleration. It sounds like popcorn popping.

Check for overheating problems:

    • Low coolant
    • Loose drive belt
    • Restricted air flow through radiator, or restricted air flow through condenser
    • Proper cooling fan(s) operation
    • Front air dam missing or damaged

Check:

    • Knock sensor circuit system for no spark retard, during the knock condition
    • TCC operation (automatic transaxle only)

Remove carbon with top engine cleaner:

    • Check to see if engine is running lean (monitor long term fuel trim for significant positive values). Refer to P0171.
    • Check for poor fuel quality, proper octane rating

Fuel with higher octane ratings may eliminate problem