N/A Detonation Ideas

[69fb00GT]

00 GT, 5-speed...car is practically rock stock (no timing advance or CAI). 70k miles. This past winter i started to hear some light detonation under accel on highway in 3rd, 4th, and 5 gears...about 4k to redline. Became progressively worse throughout the winter...I've run pure 93 through it with the same results. It's fine for everyday driving but I can't floor it with the way it is now.

Just recently changed the fuel filter and plugs. The plugs that came out where the original plats and were scary white...I replaced with autolite coppers. I was really hoping it was just a stupid fuel filter but that wasn't the case....It still pings in those gears on highway pulls.

All the plugs looked exactly the same, so i'm ruling out a clogged injector (s). I also checked the TPS (.96v idle and 4.66v WOT) and the PCV (fine).

Aside from checking the fuel pressure, what else can I check?

 

[69fb00GT]

Bump...come on...no ideas?

 

[COBRA90GT]

Did you switch to a colder heatrange when you replaced the plugs? :shrugs:

Perhaps try refueling from a different gas station? It's hard to believe that 93 octane would be watered down that badly, but maybe they are really screwing over their customers...

 

[69fb00GT]

Didn't want to put a colder plug in...it shouldn't need it.

Yep...different stations, brands, and octane's....

So far i've heard:

Upstream 02's, dirty MAF, worn fuel pump.

I'm just looking for possible causes/ideas....anyone else?

I'm going to check the FP and clean the MAF this week.

 

[mogs01gt]

This started before you replaced the plugs right? Is your car stock or modded.

 

[Mirrahasmycar]

could be: fuel filter, coils, loose hose...ect

Troubleshoot

were you really redlining in 5th? thats like 150mph?

it cuts out with the stock computer at 145mph