My SC runs like doo-doo when it's hot
 

And I mean when it's hot outside (like high 80's-90's F). It doesn't seem to matter what the car's temperature is. It hunts like crazy at idle (500-1000 RPM), sometimes it stalls, and sometimes (very rarely) it's hard to start. When the weather is cooler (70's-low 80's F) it runs very very well. No issues whatsoever.

This is driving me nuts. Any thoughts? It's an '83 SC with a little over 112k on it.

i sometimes think we SC owners need a summer WUR and a winter WUR.

i bet, if you check your system pressures, you will find that you are running the "Winter version". the WUR is somewhat adjustable. basically, your airfuel mixture is all wacked.