'04 6.0 powerstroke won't start hot after running low on fuel.

What is your question?

I ran very low on fuel and stopped at station. I filled up and when I went to start it I turned ignition completely to start without allowing it to prime (why? I have no idea! Just had a brain fart I guess) but it would not start. Ever since it will not start hot. Cold it is just fine. But when warmed up ,it won't start. Turns over just fine. Just won't fire up. I have to let it cool down for 2 hrs. And I mean 2 hrs.almost to the minute and not a minute less!!! Can someone please tell me what the the is going on here?