Car overheating while engine is off

[fixkick]

if the IAC were dead say at 10C overnight. parked, then started cold at 10C
the IAC must be open, some. (fast idle IAC mode this is)
if not the engine lacks fresh air for running cold. (IAC dead)
The ECU assumes this is open and injects fuel based on open IAC, but if stuck closed,
the fueling is now way too much (lack of air caused) and goes hugely rich burning and misfire. (3 cylinder effect is misfire gross)
the IAC is not optional, and TB are hard to find now. sure. for sure working ones.
these cars are old now and things will be bad.

forget the DP, it works, find reason for 750RPM on old engine this is wrong.