1994 Pontiac Bonneville car will not crank when hot

When car is hot (so in summer problem more apt to happen) will not start. All lights, horn everything electrical works. But car starter acts as though battery is conpletly dead. The starter has been replaced 2 times for this ( one time mechanic said that voltage was at starter so we replaced starter again which was the 2nd time ) allso new ignition key was made(key has security chip) but no help. When car is hot I must let the car cool down alsmost to point that temp gauge says almost conpletly cold. Also if I rev the engine before shuting off seems to make it worse wear car has to sit overnight before it will kick over. So again in winter it doesnt get that overheated and takes less time to cool so problem does not happen so much. Also if I shut car off no matter how hot it shows. But turn it on again say in less then 5 to 10 min have passed it will start. So hopefully you can help. Let me thank you now for helping