I'd throw proper maintenance at it first; being the cheapest and easiest start to a solution. This being plugs, cleaning up the COPs, spraying the boots with silicone spray, and putting dielectric grease in them. Then, get some MAF cleaner and clean that thing up real good. Run a whole can of Seafoam through a vacuum line on the intake, then take the IAC off and soak it in a parts cleaner bin, or just clean it up the best you can with some Brakleen. If it's still doing the same thing, try a new IAC, and test the resistances on all of your COPs to see if one's going bad.