Random idle surges in drive or reverse.
I recently purchased an 06 A4 (had K&N CAI and some exhaust work done to it already. Stock otherwise) and noticed this strange problem. At random, when coming to a stop, the engine will sputter and nearly die, so I gotta put it in neutral and rev it. Does the same when I reverse into my driveway. Sometimes it just flat out dies. A/C is off btw. Has no issues cruising down the street, on the highway, or WOT. Looked through several GTO forums and found a few people with a similar issue and took the advice of the responses.. still does it. One day it's fine, the next day it's bad, etc. Also, have yet to see the CEL light up.
However, I noticed today, when I was rolling my window down to badge in at work, it bogged down once the window was maxed out.. I let go of the switch and the idle went back to normal. Pressed it again, held it for a couple seconds and the car died. Very strange. Maybe a bad ground somewhere? Anybody have anything like this happen to them before? If so, I'm all ears.