Does not start after car heat up (after running ac on) on 1992 Chevrolet Caprice

whenever I switch off my car after running with AC on (means heat shows 50%) does not start. It simply cranks up but does not start. If I wait for a about 3-4 hours everything works fine. What stops the start, is it the fuel pump?

Asked by for the 1992 Chevrolet Caprice
I have exactly the same problem with my caprice 2006 LTZ, did computer scan but couldn't find any solution. Please if you found any solution, share with me.

Thanks :)