Truck sometimes will crank and not start

[rake18]

The truck is a 99 with the 7.3 The issue that just started and it only has happened twice now, I go to start my truck and the truck will just crank and crank and not fire. The truck has only been doing it after the truck has ran for 30-45 min then if you go out 10 min later sometimes it will start right back up or it will just crank. When it did not want to start i turned the key to the on position and let it cycle for 30 seconds and it fires right up every time. I have no clue what it could be like i said it's not doing it all the time so that's what has me confused. Any help or ideas what to check would be great. Thanks

 

[JLDickmon]

my gut feeling is it's something in the glow plug circuit, but I also have to ask, "When was the last time the fuel filter was changed?"

 

[JLDickmon]

also, was the Camshaft Position Sensor recall done?

 

[rake18]

Last winter on the Fuel filter,i am going to change it out tonight, and yes the recall was done