Just when I thought it was time for the new turbo... My A4 B5 AEB has developed a rough idle problem which after 5-10 secs settles again but the revs do drop very low and the engine has stalled on more than one occasion. After doing certain jobs involving disconnecting the battery the revs are very erratic and the engine much more prone to stalling. When I come off of the revs often I get a slight backfire which obviously indicates unused fuel. I have recently replaced the MAF sensor and Lambda sensor but this has had no effect on the rough idle although is running much smoother at higher revs. Have just given Audi a ring to see how much it'll cost for a diagnostic!?.. £112.00 Got a lead and a copy of VAG-COM from my mate but it says that my car is not OBDII compatible for some reason!! Any suggestion or ideas would be appreciated.