Hi all. I have this issue and it's really frustrating me. When i get off the accelerator there is a rattle sound around 2500rpm. It is very frustrating. It's not too loud but it annoys me so much. It also does it if I rev it in neutral.

I took it to the mechanic and he said it is coming from the exhaust pipe in the engine. I don't know ow accurate this is. Any suggestions? I will record the sound and put it up.

The car is a 06 b7 s line manual Quattro

Thanks