Possible IAC problem

[DWitcher]

Quick run down of engine details.
Goodwrench Gen1 350 crate engine 260hp. 30-40K miles. Stock other than Edelbrock Performer EPS intake manifold. Billet throttle body to carb adapter. All sensors were bought new and based on a 91 1/2 Chevy 2wd so as not to confuse the parts guy's. Distributor and injectors were bought new through GM. ECM is a 1227747 with a Howell chip to eliminate Knock and EGR. Harness is from Injection Connection and has all other stock sensor connectors including VSS which is hooked up behind a 700r4. Timing is set O* with wire unplugged. At this point the engine runs well with plenty of power for the 1970 FJ40 it's in but will not idle smooth or low (650rpm). I have been over the inital set up with the base idle and IAC setting 6 different times to get it right. The 2nd new IAC valve is having the same issue. The best I can do so far is 900-775rpm and the IAC is at 39 counts. BLM is 128-130 and INT is the same. ECM is reading 13.0v and the MAP is 30kpa. I double checked manifold vac and it was 20 inches at idle. As soon as I try to put it in drive or reverse it stalls. I can see the IAC moving in off the seat when I rev the engine. Looking for any and all the help I can get at this point. Thanks, Dave.

[Bill usn-1]

Post the logs you saved per the PMs you sent me.
Not sure why you replaced the IAC if you did the setup procedures then you should have verified the IAC operation.

What led you to replace it?

And have you done the voltage checks?