Engine Higher idle then normal

I don't have a way to check codes i need to buy a reader for it. Just was seeing about ideas and if anyone else had this problem before so i know what it could be. The unhooking of the iac and it still running is what i thought was really odd.

I'm just trying to figure out what the problem is and not waste time and money replacing parts that are good. It runs smooth other then the idle being a little too high and when i rev it it doesn't go straight back to where it's idling it hangs about 1100 rpms for a second or two before going back down to the 900 rpms. I never had one of these cars before so i dont know what's normal.