I have had an erratic idle for about a month or so now and thanks to you guys I have hopefully fixed is.
First I cleaned the MAF, no help.
Second, I cleaned the IAC valve, no help. I was amazed on how dirty this thing was at 36,000 miles.
Finally I changed the front two O2 sensors with Bosch 15716 O2 sensors. This was a pain in the A$$. It wouldn't be bad on a 2wd, but on 4x4, there's a lot in the way, and very little room to work. But, it has seemed to fix the problem, on the test drive I had a true idle again. I'll let you guys know after a few days of driving.

Rick

 

You didn't mention the EGR Valve. If it is sticking, your idle may suffer. If your IAC was as bad as you say, you may have something else going on, to get that much yuck in such a short amount of time.

 

The the PCV hose. I had problems with a choppy idle here recently and found a crack in a hose. There is a hose that runs from the PCV valve to the back of the intake. At the end of the hose there is a rubber elbow. The rubber elbow on mine had a very small leak untill I moved it around some and then I could tell. The part at the dealer cost $21 or so. Comes with a new pcv valve, hose and rubber elbow.