It's a good photo -thank you- but I can't zoom in close enough to see what's happening on your TB without going blurry.
Blocked IAC? how did you compensate? by readjusting the throttle idle stop screw? If so, did you also adjust (if possible) your throttle position sensor to reflect that change?
check and see what that's (TPS) telling your computer - that may be the source of overfuelling. a few degrees may make for enough of a voltage change to get the computer thinking it needs to increase injector pulse duration.
Another thing I need to have you reconsider is that in your equation, Pressure is NOT irrelevant. (Why bother with converting to Kelvin if you're not going to take all the units involved in the published equation into account? just because you can show a bigger number with your use doesn't mean you're correct; you can't prove what that number MEANS because of the lack of reference to units) Remember, this is chemistry...and there are physics involved before the pistons can move turning a crank and transmission and differential and wheels.
Let's walk through a theoretical calculation using Standard Temperature and Pressure (16 degrees C - 29.92inHg) and one liter (or gallon or Sh!tload...doesn't matter) on one side of that equation :
P1 times V1 over T1 is (29.92 times 1) / 16. that works out to 1.87 ignored Units.
Now, we've got a running engine making 20" of vacuum in the manifold, so P2 is 9.92inHg, and there's still one volume of air, but if it's 70 degrees because you warmed it in a hot box, the numbers now work like this:
9.92 times 1 / 70, which works out to 0.1417 ignored units.
The equation doesn't balance. 1.87 does not equal 0.1417, regardless of the units
You'd need a LOT more air, a lot LESS vacuum (when was a vacuum leak a good thing?)
More science: Vapour point and Boiling Point are NOT the same thing.
Read for yourself
Note: it mentions pressures.
You have mis-read (or misinterpreted) what I said about intercoolers. I said, "Intercoolers are used to cool the increased air charge from the turbo." Jamming more air into a container of a fixed size will change its pressure, because the Mass of air is increasing, so it's temperature must react to keep another equation balanced...and again, units matter here are we talking kilos or litres or what?
Don't change your engine - change your mind. Please. I'm trying to help you here. Start by looking at your throttle position sensor.
it has to agree with what the computer has been ingrained with (before we can teach it a new normal for the groove), and by doing what I suspect because of the IAC mod you've made, they are out of whack, and that'll make the oxygen sensor work in not-right ways...
Sorry it took me so long to respond. We'll get this machine sorted yet, I'm sure!