When I start the car cold, it idles up, and then back down just like it is supposed to do, and idles between 600-750. About 1-2 minutes after that, the idle starts to vary just a little according to the gauge, but you can't feel it. If you sit at idle for 2-3 minutes, the car will suddenly drop to barely running, cough and sputter, and occasionally stall. It will start back up immediately, but will still idle like crap. If you just rest your foot on the gas peddle, it stops doing this, and will idle just fine, and if you do this when stopped, it doesn't try to die. Also, if you drive the car after it has done this, it will eventually go back to working (2-3 minutes of driving, and it's back). This started after I pulled the supercharger off to replace valve cover gaskets, and wasn't a problem before. While I was in there, I replaced a bunch of vacuum hoses, and I've gone back over them, and none seem to be leaking. I've also redone the thermal paste between the DIS module and it's mount. One thing I did change while I was in there was; there was a catch can plumbed into the PCV lines incorrectly, so I just pulled it out, and plumbed it straight into the vacuum lines it was already hooked to. I'm leaning toward the IAC starting to fail, but I'm not sure that's the problem, so I was hoping somebody might've experienced something similar.