IAC vs throttle plate position adjustment:

Timing and idle AF must be correct first.
The IAC Position can be found on one of the screens in the data monitor (lower left area). You want the IAC position to be between 5 and 15%. If it is stuck at 0 (the idle RPM is probably above your target idle because too much air is going through the plates), you need to CLOSE the throttle plates until the IAC starts to open (5 to 15%). If the AC position is above 15%, more air than is necessary is being fed through the IAC, so you need to OPEN the throttle plates to adjust.

You must then do TPS Autoset after mechanical throttle changes.