Freaking Noise

Hi all

I dont know if someone have an idea of what is my problem. When the rmp mark 4500 and more in acceleration, i have a sound like if i have a turbo under the hood or like someone open a windows when u roll. Someone have a idea??? i very confuse:banghead: I have a 2002 envoy with 4.2L Sound like exhaust problem???

Thx folks

Welcome to AF, virtually impossible to accurately diagnose noises in this environment, I can tell you the fan clutch can make this noise, but without hearing that's about it. BTW I drive the same truck and other than the bad fan clutch I have not had this type of noise in 100k miles.

Max could tell by listening while driving it. That f/c is such a common failure, sounds like a jet airliner under the hood. If you wanna run that trap on the cheap, see if you can find a reputable independent mechanic who works on TBs & Envoys, let him test drive it & listen to it. If you have to replace the f/c, be advised there's an updated version with a 152xxxxx part # and a GM bulletin on installation and re-flashing the PCM.