I have an o4 dmax that at around 30k has developed a fuel knock under slight load or acceleration. It is a loud tick from 1400 rpm to around 2200rpm. Sometimes it gets real loud and increases with rpm. The idiots at the dealer checked the truck on the scanner and fuel return rates and tells me it is normal. we went for a drive and with the fuel pressure lowered just slightly, the noise is gone. they have no answer but to tell me it is a fuel knock. any ideas guys?

I had the same concern, I was able to eliminate the noise by cancelling one injector at a time with the Tech 2 until it stopped. That is what your dealer should try. This will tell them which one is at fault. I still replaced all 8 in mine, but only because I can:D

Mine does the same and its real bad. Sounds like an old gas burner thats got bad fuel.Do yall think i need injectors?

My buddy had the same problem. Turned out to be a short in one of the wires that controls the one injector. It was rubbing on the support bracket. The problem would come and go. Chevy had a bulletin on the issue for 04's.

Mine truck has that sound when taking off from a stop. Sounds like pinging/knocking/clanging of valves like gasser out of spec or valve job.


Any techs here know anything about this?


LATER!