Did you do a search? I'm sure this has been brought up before?? The I/H/E should have no effect on the idle. If the car has a fouled O2 sensor, and/or cat issues a CEL would reflect that, but rarely affects the idle.

In short: You need to check any and every vacuum line running to the IM, not just the IACV. Also attached to the bottom of the throttle body is the fast idle control valve: to check it, detach the intake pipe from the throttle body let the car warm up (fan clicks on at least once) then put your finger over the hole in the lower left, if your finger gets sucked onto that hole...there is your leak.