The IAC is controlled by the engine management computer. So, you'd need to reprogram. You could try to kluge it by adjusting the throttle blade stop screw, but that would make it rev too high when in park or neutral.
Best thing I have found to smooth out the IAC rotation is to spray it with carb cleaner to get the crud out, then drip a few drops of motor oil in it.
Seems to work & last much better than the lightweight sprays.
Don't remember the exact idle speed spec, I think it's 600 in drive, an eases up a bit in neutral/park. Regardles of the engine condition, the computer will strive to hit the 600, and a good motor will run smooth as silk at that setting, maintaining it with or withour the AC on. So if it's running rough at that RPM, then there is another problem with the tune, vacuum leak, engine mechanicals, injection, etc.

DG