You have to be sure that the pintle in the new IAC isn't out too far before installing it (28mm from the face of the mounting flange to the tip of the pintle cone). Then theres a short procedure to reset the pintle once the IAC in in place turn ign on, then off for 20 seconds, then start the engine). Make sure the passages for the IAC are clean.
Sounds more like an unmetered air problem to me and the throttle plate needs to be put back at stock.
With the throttle plate back at stock and the engine idling... if you unplug the IAC, does the engine stall?
