spark knock

Help Anyone?
I have a 2000 GMC that has a pinging problem that I'm trying to get resolved before real damage occurs. It pings as soon as you tip the the gas or during cruise speeds as soon as you touch the pedal. It pings with all 3 grades of gas and even with octain boost, although not as bad with 93 octain, but can't afford to run that all the time. There was one TSB out there to try, with replacing knock sensors and building a dam on them with silicon, it worked for a week and is now worse than before. I know of 2 other people with 2000 5.3's with the same problem. Thanks

BlownChevy

iTrader: (20)

Verify that your EGR is working! What are your mods if any?? If you have a K&N check your hot wire in the MAF, it could be dirty.

spark knock

I don't have any Mods, and we have sprayed out the MAF and the scan tool says the EGR is working fine. My friend a mechanic had suspected the MAF at one time, it was in specs, but at one end of the sectrum. He now has an Burban with a 5.3, so our next step is swap MAFs Just rule that out. He also has seen a few intake manifolds lately on these that don't look like the gaskets are sealing as well as they should be, (warped or something?) thanks

Black Blown 02

Check the PCV valve and tube it connects to for oil. I've heard some trucks will suck oil through the PCV into the intake, and that causes bad pinging. I think theres a tsb on it and a different type of PCV valve.