I thought I had an IAC problem which turned out to be the MAP sensor located on the driver side fender well next to the fire wall which is housed in the metal rectangular box and mounted with two screws and has a vaccum hose. After normal operating temp. the symptoms were idle hunting from 1200 rpms to 2300 rpms. The rpms would come back down to idle speed if I manually brought it down by putting it in gear but if I put it back in nutral or park and slowly accelerated the rpms would jump back up to 2300 rpms and start hunting. Also I never could slowly increase the rpms, as soon as I touched the accelerator the rpms would jump to 1200 rpms but would return to 750 rpm idle speed upon releasing the accelerator. I purchased the map sensor from Auto Zone for about 41 bucks. The part number is SU105TG the brand is TruGrade. IT is a GM part number and is a lot cheaper than volvo and is the same sensor. Hope this helps someone. Larry