The thing that really stands out to me is the IAC is at 0%. First thing I would do is block off the air supply to the IAC, this is the kidney shaped hole next to the throttle blade directly above the IAC valve. Is there any air at all going through that valve? With 0% I there should not be any air at all. If there is air going through that valve then either the valve is bad, wiring, PCM, or the computer just hasn't learned the home position. See post number 6 by TriumphR3 above.

If there is NOT any air going through the IAC valve then you have too much air getting in some place, the most common place is the mounting gasket for the TBI unit, but you already replaced that. I use propane to sniff out vacuum leaks on the engine itself, typically a missing vacuum cap, compromised vacuum line, the PCV valve, or intake manifold leaks at the gasket. You can use carburetor cleaner to do the same thing, but it tends to puddle and is a severe fire hazard. Not being able to see the fuel trims makes things harder but you should be able to hear a vacuum leak because the engine will smooth out and speed up.

Do you have access to another scanner? There are a couple of other things that your scanner is showing but that IAC percentage is the first place I would look.