Not wise to mess with the idle screw in most cases, after you clean the IACV (or before) you need to make sure it's at, or at least close to, the correct base idle. With the IACV disconnected (but on the manifold) and the engine up to temp. you need to adjust the idle screw so it's at the correct base idle for that engine (whatever that is). Then, after hooking the IACV back up, reset the ECU.