I'm hearing a humming or buzzing noise that goes up and down with the revs... it sounds familiar but is suddenly getting louder each day... does this sound familiar to anyone ?

 

2001 TTs had an incredibly irritating and loud buzzing vibration, especially sensitive to bumps and brick streets... the source of this one is under the backseats where a cross strut vibrates against the sheetmetal. I wedged leather between the two surfaces at several points with 100% improvement. There is a tech. bulletin on this issue.
Good luck
Tom

 

I just got a call from my mechanic this morning about this. He originally diagnosed the problem as a bad power steering pump. When he changed it, it sounded the same. Today he found it was one of the pulley bearings for the serpentine belt. That part was $200. The power steering pump and reservoir were $1400. Unfortunately I have to eat that, but did get the labor refunded.