Noticed recently that my engine is rattling more than it used at idle. It seems to do it after a run when the engine is hot. I can hardly hear it in the car, its when i get outside i can hear it. I'm not confusing it with the normal 'ticking' that it and my last A3 had (charcoal canister i think?). This is different, it almost sounds like a diesel! If i raise the RPM even slightly, it stops! I had it serviced including an oil change/flush and cambelt/tensioners/water pump replacement about 2 months ago and it was remapped shortly afterwards for info. Can anyone help me diagnose? Thanks.