Hi All, I have just bought myself a lovely A4 Cabrio Auto 3.0. For the first day (yesterday) It ran like a dream, what a lovely car, smooth, fast and comfy....then today after running it for a little while. I stopped, and restarted about 10 mins after stopping and it has started to judder (the Revs keep going up and down) and making the car shake. This only happens when in Park or idle in gear (but not as much and when in P). No engine light, no issues while driving, but even if I put my foot on the accelerator, it will jump from 1000 to 1200 and then back down to 1000....doesnt seem to happen over 2000......Not happy and a little worried....I bought it from a 2nd hand dealer in Wembley but really not sure what it could be. all oils and fliuds are all good. Engine runs great when im going....Anyone had anything like this before? thanks folks