lb7 no start

Lb7 2004 no start no crank after driving it if it sits for a hour it’ll fire up no problem battery’s are good when it enters the state of no start I can jump the starter or the relay and turn it over but will not start until sitting for a hour and whenever I get it started I can turn the truck...

I got a 2003 lb7 duramax with 320000 on it, I’m having a weird problem with it. When it sits say a day or two it fires up without a problem but when I shut it off after even 20 seconds of it running it will only crank and not start. When it sits the desired fuel rail pressure and actual fuel...