Steven Petersen
I'm Awesome
There really isn't a "fast idle" spec on the .bin for a 7747 ECM. When you shut off your engine the IAC goes to its "park position", in this example it's 145. Then, when you start the engine, it waits 20 seconds before the IAC starts to decay to set position vs temp. Here's some of the tables controlling the IAC. In this case it calls for your IAC to be ~24 when warm and your idle s/b ~600 in Closed Loop.
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Agreed, your IAC position at warm idle appears to be high. Plus your idle is high too. As @Schurkey suggested, clean the IAC passages. Maybe they're choked down a little causing the ECM to open the IAC some more?
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Try turning off your ignition, wait about 15 seconds, then turn it back on and see where your IAC is. Theoretically it s/b ~145 steps in park position (I think, ha ha).
How old is your O2 sensor?
O2 sensor was replaced with new Delco 9 months ago, only because I bumped and broke the old one while working in the vicinity. The threads were bad and I had it tap the hole to get the new one in. Would an air leak at the threads be a possible problem?
Another thing I just discovered. The butterfly in the air cleaner was stuck in the open position, meaning it couldn’t shut and pull warm air from the manifold. I was able to free it and now it works properly. I’m hoping this helps during warmup.