I've got a running problem with my A3. I picked the car up about 3 weeks ago and have noticed it has a problem when the revs get to around 2k rpm. It's apparent when driving, but also when parked, it's also impossible to hold the car at 2k rpm. The revs bounce up and down by around 300rpm either way!. The cars been checked for fault codes but doesn't have any. I've also tried unplugging the maf, but that makes no difference. I have been back to the dealer (Mercedes), who took it to a local independant. They acknowledge that a fault exists but don't know what it is and have advised taking it to Audi. The Dealer is reluctant to do this. Anybody got any clues/experience of a similar problem?