Detonation/Spark Knock/Pings
A mild to severe ping, usually worse under load or acceleration. Sounds like something is rattling or knocking in the engine.
POSSIBLE CAUSE ACTION
Incorrect spark timing Check Spark Controls (EST, ESC ...etc) Chart C-5 Electronic Spark Control (ESC) Check
Poor or contaminated fuel Recommend higher grade fuel
Overheated engine Check coolant level, cooling fan and thermostat operation