Car dies at operating temp 2001 pontiac firebird

How long since a tune-up? Any applicable trouble codes? Does it stall at idle or going down the highway? When problem is ongoing, if it cranks good but won't start, have a helper crank it while you check for spark at the plugs,--proper fuel pressure, fuel injector pulse. If the engine is hot, wear gloves. If you missing everything I check for rpm signal, comes from crank sensor. I'm not saying replace anything, you need to do some testing. Another thought is over-fueling. Too much fuel in a hot engine can kill it and no start. Once the engine cools over a period of time, the extra gas evaporates and the vehicle starts. Check the coolant temp sensor. Use a gage and check proper fuel pressure, 48--55 psi, key on engine off, so if reading is in the middle, should be fine. After proper fuel pressure, turn off the key, the reading should hold for a bit, does it? If the pressure drops like a rock, you have a fuel pressure leak, could be fuel injector leaking? good luck.