Anyone know how much fuel the IAT can add or subtract?

Hard to say.....
 

I would guess it would add fuel at low temps during cold startup, but at WOT, it would add fuel at higher temps.

I'm looking through the 1.8T maps, and there's about a dozen maps/functions dealing with IAT. Some for timing, some for fuel, some for ???, and they are used under different conditions, cold-start, part throttle, WOT, etc.

I'll look through some of the code and see what I can find and I'll post it here later.

Did we just find the problem Rob?? Damn Bosch manuals anyway <throwing in garbage>

JB, have you had a chance to check this yet??

Nope, been too busy...
 

still working on it.