I just parked my car after cruising for awhile and when i heard a strange buzzing sound from the rear of the car. So i go to the back and craawl under a lil ways and it sounds like a throbbing buzzing noise....like buzz...buzz...buzz....buzz. Like metal vibrating against other metal at a high rate. its not as constant buzz it throbs. Sounds like its coming from under the car by the rear left tire. I thought maybe it wasthe heat shielding around the exhuast buzzing on the exhuast pipes because it had gotten really hot....but I have no clue what it could be? Anyone had this happen before. Also does anyone know were i can get a diagram of all the vaccum lines in the TT Z?