Have an '03 A4 quattro3.0L w/ tiptronic. There's a noise coming form the engine compartment when the the engine revs down. The noise sounds like a jet engine and happens between about 2000 rpms and idle. It is noticable after the vehicle idles for about 3 to 5 minutes. Thoughts

Thanks for any help!!!!

 

First thing that comes to mind is the secondary air pump but the timing is off. Also check your electric fans. Maybe one of them is coming on.

 

is it like a whistle/whine??? and it sounds like a jet, lol.... does it start whinding down if you let off the gas at 5k RPM's in second gear?? I think i might have the same noise and its either a pulley or a belt or something like that.