Hello,
I have noticed that when my 99.5 A4 1.8T manual is at slighly too low RPM a metallic, almost buzzing, intermittent vibration comes on if I press the accelerator a bit too much. It then goes away when the speed increases. While I would expect some overall vibration from the engine, I would not think of hearing anything from beneath me. Could it be the heat shield touching something? Should I worry about it?

Any tips will be welcome.

PS: I love this sight!