Erratic idle with codes 22, 34, 35 and 45

I am unable to find a mechanic in my area who still knows how to service these old cars and has the computer to do it. I’ll keep searching maybe some small obscure shop can do it.

Based on some things I’ve read and what you’ve said, I tried blocking off the EGR valve with a piece of sheet metal between it and the throttle body. It didn't affect the idle, it just made the code 45 rich exhaust stay on all the time. I also tried the opposite blocking off the vacuum line going to the EGR to hold it open, still same. So I guess the EGR is good.

I also blocked off the vacuum line to the MAP, still same.

I unplugged the MAF just to see what happens and it seems to make it a little better, it doesn’t surge all the time, just intermittently. But If I put it in gear with the MAF unplugged, it stalls. I swapped back in the original MAF and it didn’t make a difference.

The only time it will fire up and run without fail is if the IAC is unplugged, but it idles super high and seems like its going higher as time passes until I shut it off (scared). But I have already replaced the IAC (twice).

At this point I’m grasping at straws until I can find a shop who can run diagnostics on it. Anyone have any ideas at all I can try?

For now I’ve adjusted the throttle screw until it just barely keeps it going with only very slight surging (you have to be really listening to hear it). It runs good now, as well as will start again without giving gas. Check engine still comes on occasionally for code 45 but this should serve my purposes as a “utility vehicle” until I can get the diagnostics done.

Thanks for all the help, I’ll let you know if anything changes or if I manage to get a scanner on it.

Update: I found this info on a F-body forum: https://www.thirdgen.org/forums/tpi/131292-iac-idle-screw-must.html

See the section Throttle Minimum Air Position Adjustment.

After doing that process, that I have eliminated the idle surging entirely. I guess the IAC and throttle needed to be calibrated after replacing the IAC, which I did not know.

I'm still getting the code 45 rich exhaust but I’m willing to deal with that since this will be mainly a utility vehicle. I just didn’t want it to surge and stall on me when I’m hauling stuff around.

Thanks again for all the information and help!