CamaroSS27

iTrader: (6)

I just recently installed heads and replaced my IAC because the old one I was lead to believe was bad because my idle would pulse up and down until the motor was warm. But now the car will start and turn off or barley start then rpm pulse and it dies. I unplug the IAC and it will start perfect. Now after driving for a bit and I go to neutral sometimes it will idle at 1800 rpm for about 10-20 seconds then rpm pulse or just goto normal idle? Everything kinda happens randomly could this be needing a new tune or my IAC? I ask because I went from 241 heads to 243, I already had it tuned awhile back with bolt ons and cam.