96GT226410

I did a PI swap along with new timing chain tensioners on this car, but my last 4.6 had the same problem and I only did timing chain tensioners and it worked.

2002silvergt

i can just about bet you its detonation...my car used to do it until i put all my mods on and got custom dyno tunes via an x3..

teal94_stang

another one for detonation. my car used todetonate at WOT and i backed the timing off and run 93 octane.

Quicktime_GT

yeah try different gas

dch61407

Thanks guys, I filled up with 93 and ran it a while and got on it good, problem solved. I thought these cars only needed 87. I dont care im just glad I solved that issue. Im ready to sell the car now because I keep running into more problems and ive only had it a month. I never want to buy a carwith mods again because you never know what all really has been done and how good it was done. I would rather just do everything myself. Just thought id say what was on my mind. Thanks again

radjxf

I'd be curious as to what's causing the "spark knock" as I call it (detonation). Your sig line doesn't indicate anything that requires higher octane levels. Wonder if the timing's been advanced by a tuner perhaps? My 02 GT runs fine on 87, but slightly different engine. Glad it worked out.

dch61407

Yeah Iam curious as to why the 93 worked. Thats why im just about ready to sell it because I really dont know what all has been done to the car, bolt ons I can handle because thats easy to reverse and its obvious, but anything other than that I wouldnt have a clue

cliffyk

As the miles rack up it is not uncommon for carbon deposits in the combustion chamber and piston tops to effectively raise the compression ratio--this happens a lot on cars that are "babied" (like the people that have posted here saying they always shift at 3k).[/align][/align]You need to wind 'em out (which is quite different from beating on it) every now and then to blow out the crap...[/align]

lizzyfan

I figured it was detonation

dch61407

Thast kinda funny he said you need to get on it more, because I have been doing that to, I dont really get on it to much about 5k is about the highest, I dont like getting close to the redline, it just bothers me. It is running better but the 4:10 gear just has me shifting to often, I dont like it, It seems like I have to cruise around town in 5th gear all the time without riding the 3k mark at like 45-50mph in in 4th. It sounds really good but I know its hurting the gas milage for sure