I have a buzzing that comes from somewhere in the transmission tunnel. It sounds almost like a heat shield. It is most audible from the shifter area. It occurs at light throttle at any rpm in any gear. Typically around 80-95kpa its silent anywhere above that.... Which is inconvenient because that is where I typical accelerate in normal traffic. Any thoughts It only happens on throttle never when I lift. I can't seem to find anywhere the exhaust might be hitting

 

Get under the car and start hitting things with a rubber mallet. When you hear your noise, you found it.

On my car it was the downpipe shield.

 

This sounds like heat shield rattles, keep tightening bolts and adding hose clamps until it goes away.

 

Don't forget the shield around the cat, if you still have the OEM one.

 

My cat heat shield rattles something terrible on acceleration. Wrapped it with a coat hanger (ghetto, I know) to stop it until I get a new one.

 

I have a diy exhaust setup. So the factory cat isnt the issue. The chassis mounted heatshield might be the issue but I doubt that. im guessing its a gasket somewhere that is gone. I also know my rubber shfiter boot is all but destroyed. so the sound transfer is probably much more notable.