It would idle about 1300 rpms and never back off. Im pretty sure its not a vacume leak. I have not found one yet. I thought it might be the IAC, so I got a new IAC. Put it on... and back to idling high. The only thing I can do to fix this is to manually move the plunger myself. So I have it set at 750-800ish rpm.

Another thing I noticed when i start the truck (warm or cold) i have to give it a little gas to keep it running. It will bog down the idle up a little, bog down idle up a little. Then after a few sec. its ok I can drive, idle fine. Any ideas?

 

I have a 98 LS1/A4 swap in my truck and I'm having very similar problems. Mine has done this idle searching at startup that you speak of ever since I first did the swap. I always blamed that on the cheap tune I have. Now, about 2 years after the swap it has started to do this high idling thing intermittantly. My first guess was a vacuum leak so I replaced a pcv T that was going bad and it went away but only after I reset the pcm. Now about 2 months later it's doing it again. I don't know but it sounds like we have the same problem, if you figure it out let me know & I'll do the same.