When my cars idles when its cold my ass and kidneys vibrate. The tach reads about 600 rpm. It is most noticable after I drive after starting in the morning and then stop at a red light. After the car is warmed up, the idle is smother at approx. 700 rpm. It started doing this at about 30k. I have 47k now on it. Dealer "cannot reproduce problem" even after I left overnight. I don't know how you could miss this idle vibration unless you don't have an ass. The car runs perfectly otherwise. Original owner of 97 TT bone stock except for cat back HKS dragger. Put up and shut up or do something about it??? Thanks in advance. Great forum.