Pulling my hair out...

Is there a way to disable all IAC functions and then introduce them back one at a time.

I have changed just about everything i can and just not my tuck insist on going back to 850rpm for no reason. It was at 700 for an entire day and now, back to 850. I changed nothing and I am in closed loop.

no programming will manually change my IAC counts, But idling at 850, I drop into gear, goes down to 700 and i can watch the IAC count up trying to reach 850.

I do not understand all of the decay/timer scalars with %s of this and that. Should i toss my 1228747 $4F ECM and switch to a 1227747 or something different.

Side note, I have looked a a few late 80 suburbans to buy and they all idle high. Makes me think it is a EMC defect?

Thanks,
Chris