1999 crown vic stalled at an idle (outside temp 100 degrees). Starter cranked just fine, but wouldn't turn over. 30 minutes later started right up and took me home (approx. 1 mile). 8 o'clock that night, drove 6 miles - no problems.

Are you saying it won't crank, or won't start ?
If it does not crank, and you have replaced the battery and starter, the problem may be in the neutral safety switch.

Idle air control valve. And/or gunked up throttle body, pcv port at throttle where mating to intake manifold.

The cavalier 2.4L engine had a problem with the crank sensor intermittently going bad. Sometimes it will run sluggish for a few minutes or even stall but eventually crank back up and run fine. The sensor is about $30 and can be changed in 10mins. It is located directly above the starter.

have a 97 crown vic,
in warm weather it idles fine and run fine
now that its cold I have to hold at high idle to have warm up
for about 10 mins.
if I just start it the engine will die with out me holding on foot on the gas

can check these codes (if any) by jumping the A and B terminals at the diagnostic port under dash with key in on position engine light will flash and have to count flashes also sounds like it may have an air bound fuel system

Was the fuel pump checked out?
Have a scope put on it,to check for a worn armature. May also be binding up mechanically
Also check TPS Sensor data or scope it

Timing belt/chain may have been put it slightly off time, when motor rebuild

This is caused by the IAC valve. Over time the valve becomes gummy and inoperative. Get it replaced and the problem is solved. IAC stands for idle air control, hence the stalling concern.

perhaps you have a sticking IAC valve. Idle Air Control valve. pretty common concern.

try changing temp sensor could be your problem