High idle with new engine
 

I have a '93 rocket that has just had a transplant. A new build with new housings, ceramic coated and clearanced rotors, 3 mil Apex seals, '99 Spec Turbos, Dowel pinned block, street ported and polished, Power FC and commander, oil gallery mods and high flow oil pump, high press fuel pump, cold air intake, stage 3 clutch, new engine wiring harness, O2 sensor etc etc..... Lots of go fast and reliability. I think I can say we left very little undone.
I've put around 1300 miles on it now.
But here's the thing. After a surging or hunting idle that went from 900 to 1400 rpm, I have adjusted idle screws to get a steady idle of around 1500 rpm. No more surging, but way too high, and I'm having a hard time trying to get it down to a reasonable level. Bypass air screw all the way in and its still too high. TPS adjustments don't bring it down either. Most solenoids, relays, and check valves were changed and there is absolutely no vacuum leak. I'm going to try swapping the Idle Air Control unit and see if that's it. I can get my hands on one that isn't in use at the moment strictly for trouble shooting. Its about the last thing to check.
the engine was built by a very reputable shop and I won't post the name as I'm not sure if that would break any rules or policies here. That shop is more than a day's drive from here and it would cost me around $500 in gas just to get there. I've considered the drive so the guy that built the engine can see if he can resolve the issue. I have complete confidence in him, but it would be inconvenient to say the least.
any suggestions?
Thanks......

You said there is no vacuum leak, but did you check?

Yes, we checked with positive pressure smoke. No leaks.

Turn the idle down to where it is hunting between the 900-1400rpm. its probably just the power fc trying to learn, it does this, especially when new. Give it a few heat cycles to try to sort things out, or you can also search the power fc part of the forum for the idle learning process, and try that.

Do you have cruise control?If yes check the cable.

Yeah, I thought of the Cruise Control cable the other day and checked it. Its fine. And as for the Power FC learning the engine...It was recommended by the engine shop that I allow up to 1500km to learn, but I've got nearly 1400 miles on it now, and the consensus is that the Power FC should have done it's learning cycle by now. But thanks for your input. I will search the Power FC section.