I just finished a 24x conversion along with a procharger and had it dynotuned. Everything was good for 100 miles, but now when I come to a stop or when I start the car, the idle drops to like 400 rpm for 20 seconds and then comes back up to normal. Does this sound like a problem with the IAC?

 

Let's move this over to the "Forced Induction" forum. Sounds like it might be a problem specific to the supercharger.

 

You can try cleaning the IAC but that's only going to be a shot in the dark. You need to scan it with HP Tuners or EFILive to see exactly what's going on.