My '97 is almost completely stock (!!) at 68,000. Has had EGR campaign performed at dealer about 1 year ago. Knocks on premium fuel (even with octane boost and 2 gal. of 100 octane!) at part throttle after warm-up. Replaced 180 therm. after overheating problem - cured overheat but not spark knock. Dealer mech. suspects EGR port blockage(haven't checked). Was wondering about simple carbon build-up? Cleaning suggestions? Problem seemed to start after install of 255/55R16's - much taller than stock - reprogramming necessary to compensate?

 

Has the knock system been checked? There is a procedure to check the sensor while it's on the engine with a volt meter. I don't have the book in front of me so I can't remember. May be some one can volunteer that if you reply. I know it will detect a slight rapping with the back of a screw driver and the meter will show when you do. But beyond that I forgot.

Also do you have access to a scanner? The Snap-on one shows total advance when running in real time. Could be helpful to see what's going on. Maybe a local mechanic has one and is willing to hook it up to check. Just a thought

 

I hate detonation problems with these cars....FWIW...I have been having detonation/preignition/something like that problems for about 6 months. I have changed every sensor, plug, wire, liquid...seafoamed everything, bought AutoTap and LT 1 edit. NONE of it has fixed my problem. I dont have any clue as to my problem either. Mine detonates from about 1400-2400 rpm in any gear....then it goes away till the next gear at that rpm. Well, I hope you/I figure out our problems. Im guessing that since programming doesnt help it...that my problem is internal (gasket leak ??). Hope someone can help us.

Get back up there!