I just solved a cold start problem on my 740.

The small adjustable link from the throttle 'wheel' to the throttle shaft itself was set with not too much play at idle. Worked fine until temp got down to about 20F, then the car would start, but no fast idle. It ran rich and slow and eventually died.

Apparently there is some different expansion rates in this setup that, at cold temps, all the slack was gone and it opened the throttle enough to activate the throttle position switch.

I adjusted it so there is more play and cold starts are fine.

This morning at -11 F, no block heater, and it started right away.

BTW do check for clean throttle body and linkage.

Good luck.