I've been having some idle issues with my 2002 Accord Coupe EX 4 cylinder (F23A1), Auto. When I come to a stop in stop and go traffic and after the engine warms up, the engine will hover around 200 rpm and will sputter out and stall unless I keep it alive with some gas. I've tested it this with the A/C on and off and that makes no difference. Now I know this sounds like IAC valve, but I've had that checked and the mechanic said it was clean and fully functioning. I also don't have any idle surge whatsoever. There are also no check engine lights associated with these occurrences.

I had an idea the other day to try out shifting into D3 when I slow down below 30 mph, to see if that had any affect. Surprisingly, I've had no troubles all week and my car seems to have better throttle response as well. So that got me thinking, could it be that the transmission is causing the engine to stall at a stop? Specifically something to do with 4th gear?