924doorEG

Hey guys weird thing happening kinda want some awnseres if anyones has any....so i noticed about a week ago that my car only in 4th or 5th gear has a slight knocking sound when i push on the gas a little but if i stomp on it it goes away, (or i cant hear it eaither way) and if i let off the gas and wind in down it its not there eaither. it only happens if in between 2k to 3k rpms max and then it goes away. This only happens when its driving absolutly nothing at idle! The only thing ive replaced lately was driver axle and half shaft and that has nothing to do with it im sure. But i did notice today when the car was at idle and i reved it up the rear motor mount kinda flexes up??? not too sure if that has anything to do with it. i got a valve adjustment about 12k miles ago, and im sure its not a rod knock because it hasent gotten louded and it goes away, and ive been getting on it a bit lately too so if it was a rod knock i think it might have went out already lol.....Anyone please help any suggestions??? motor mount?

Former User

Please create thread titles that summarize the tech problem (see stickies at top) - edited.

You may have a spark knock problem. Check the ignition timing and try a new gas station.

Definitely fix the rear mount as well.

924doorEG

Sorry about the tittle man....but isnt spark knock detonation? if so thats not it because i have detonation a little anyways....but i checked the timing which is pefect, and i put new gas in and it didnt make it go away. Any other suggestions? can a rear motor mount make that knocking under these conditions?

Dioxine

Detonation is a bad bad bad bad thing. A little is still a huge problem. It get worse in higher gears because your motor advances ignition. You will need to retard you ignition timing regardless of whether or not its perfect. Are you jumping the diagnostic plug whenever you set the timing?

Jdubbs6101

Yeah sounds like detonation to me has your car been dyno tuned or is it a stock motor and ecu

Former User

It could also be a pre-ignition problem caused by carbon build up in the cylinder. In this case, consider a Seafoam treatment.

924doorEG

Yeah im not sure what iot is exactly.....the detonation i have is only in a high gear if i just floor it and bogg it out it sounds like somthing rattleing under my car lol....But this knock is somthing ive never herd before. And i know for sure its not a rod knock because lastnight all night i would let off the gas when i hear the knock and let it slowly wined down and the knocking will stop. And as far as my motor and ecu its bone stock, and the ecu is a base mapped p06.