IAC is the bypass looking thing in the throttle body. Open throttle spray in there, take a toothbrush and scrub walls and edge of butterflyand then rinse out, spray loads in the bypass hole (IAC). start it up, might take a few cranks as it is "flooded" as it idles spray in the IAC hole until it almost dies, do this as often as you can with your can of Gumout or whatever. Seafoam is an entire system cleaner, 1/2 sucked into the intake, and the other half in the tank. When you suck it into the intake through the power brake hose or whatever vacuum hose you can find, let it sit for an hour or better yet overnight. When you restart it, it'll billow white smoke like a sky writer until it burns off.