I had a similar, if not identical problem on my 740T.
Did all of these things, and the problem disappeared:

Inspected all non-cooling hoses. Found few cracked ones,
few loose ones, and few where nipples were totally or
partially blocked. Removed and cleaned flame trap,
and hoses attached to it.

Unplugged all electrical connectors in engine compartment,
cleaned, greased, and re-plugged. Did the same with electrical
fuses, and under the car, to fuel pump connections.

I didn't do this, but it could also be the temperature sensor.
If it thinks the temperature of the engine is warm (although it is not)
it will send wrong signal to "computer" who in turn will not send enough
fuel to cold engine.

Good luck !

p.s. By the way, what are you doing with your original IAC ?
I could use one...