Spark Knock/Detonation

Check for engine running hot because of low coolant or other cooling system faults.
Check for correct fuel octane rating.
Check knock sensor (if equipped) and circuit.
Check for correct PROM or EEPROM.
Check spark plugs for correct heat range.
Check ignition timing.
Check for low fuel pressure.
Check EGR system operation.
Check automatic transmission/transaxle for correct shift points.
Check for carbon build-up in cylinders.