General Maintenance & Repairs - Knocking at very high rpm?!

Ok fellas, i'm having trouble tracking down a high rpm knock. I changed the plugs, wires, fuel filter, cleaned injectors, fuel system, MAF, and AIT sensors.

It wasn't doing it for a while and it seems like the cold weather brought a knock with it. What do you think it could be other than that lame diagnosis? :lol:

probably detonation/ping

probably detonation/ping

Yup, that's what knock is all right...

Two quick thoughts:

Vacuum leak?

Any oil consumption?

I'm assuming you run premium of course. Got a fuel pressure tester?

[QUOTE=Formula413;10595234]I'm assuming you run premium of course. /QUOTE]

That's right. If you are using regular or plus look no further for your problem until you run a few tanks of premium through it. And then always use the highest octane gas available to you.

Always run 76 brand 91 octane. Not sure if a i have a vaccum leak, i tried checking all the lines even spraying them w/ brake clean to see if the idle fluttered. Got nothing out of that. No abnormal oil consumption. My old Z used to eat oil like a fat chick with a 1gl. bucket of Haggen Daz :lol: though so i know the signs of that one.

I'll try the fuel pressure tester. Think my fuel pump might be going out? It does have over 100K on it.....

bad A/F ratio can also cause knock

thats the way mine started ended up having 4 spun rod bearings and two cracked rods,only had 59,000 miles

If you suspect it of pinging, how is the fuel pressure/volume?
Sure it's not the motor internally?
I see your in cali, on the far side could also be a busted cat, since you have to run them there.... Seen that mimic the noise of spark knock before.

I am not going off the sound alone, i am able to see it on the scanner. It peaks and holds about 3.5-3.8 knock retard

Figured it out, checked the spark plugs again and it stopped. Guess i got a bad batch. :confused: