93 grand prix hot engine stalls

My engine starts and will run fine but for only a few hours. Once it gets hot it will stop and will not start again till it cools in 15 or 20 minutes or so. Could this be a transmision problem?

I doubt it's a transmission problem since it seems engine related. Common causes of a stalling issue when hot include the ignition module, crank position sensor, fuel pump and ECM. You'll have to do a little diagnosis to determine if you're losing spark, fuel pressure and/or injector pulse to narrow down your choices.