You sure its not overheating-did you check the EGR it will cause detonation if its not opening-Knock sensor not retarding the timing
If the insulator is split or chipped, detonation (spark knock) may be occurring in the engine. The underlying cause here might be an inoperative EGR valve, overadvanced ignition timing, excessive compression due to accumulated deposits in the combustion chamber, or engine overheating.
Friday, April 6th, 2007 AT 7:20 AM