2000 Ford F-250 wont start when hot

Okay heres my situation. When the weather is warm outside and I get in my truck to go just down the street or even to work after I shut it off I have to wait for sometime for something to cool down before it will crank again. It will spin over fine but just wont crank, but when its cool out I can turn it off and on and go from place to place without no worries.I have done replaced the air filter and I am going through my chilton book through the process of elimination. Was just wondering if anyone could tell me what was wrong before I replace things that aren't broke, because according to my book it could be the ignition coils, the crankshaft position sensor, the camshaft position sensor, or a few other things. But a sensor doesn't seem likely. Thanks for your help