Hard Staring when Hot (Buick Regal 1996)

Just purchased the car. Prior owner took very good care of it. 172,000 miles. very quiet when running. Today in temps of 100+, I had difficulty starting. I had to sit for about 10 minutes attempting to restart again and again and finally, it sputtered and sputtered, like it could not maintain ignition/fuel/?? but cleared up after a while and ran to idle. No problems when running or driving. This only occurs when restarting after running engine. I am guessing the heat has something to do with it, but not sure.
I am suspecting either the crank sensor, fuel pump relay, ignition coil, and last, perhaps the ECM?
Any suggestions?

Last week after driving the car a little while during another hot day, and it had difficulty starting but, just sputtered a bit on first try and then caught on after a little patience.

REPLY ASAP, my daughter is driving it to her school and she has to get going once this is fixed. I won't b around to help her out being miles away, that is why I need positive diagnosis as early as possible.

Thanks!!!
JackalABC

Thanks! Really Helped!