First off ive searched past threads on this subject but havent found my answer for sure.

pickup ran fine all day, drove about 180 miles including shutting it off and restarting it a few times, pulled into get fuel, went to restart and it wouldnt go. A couple times it would almost go but then nothing.

Tach was moving while cranking, Oil level was full and clean looking, 22 maxi fuse for ecm was ok, put new lift pump in last winter so dont think that is it, fuel filter looks ok as well as fuel level in bowl, opened drain to get rid of any water. Got it to start finally with ether (spray and crank no glow plugs of course)  ran very erratically like either starving for fuel or not hitting on all 8.tried switching tanks no difference. Valve cover wire harnessess have been replaced last winter, checked to make sure they were all plugged in. tried to take plug out to check hpop level but the allen head stripped out. but dipstick shows full oil.

So now i am thinking of trying cam sensor even though tach moves and it kinda runs, or i have a fuel delivery problem of some kind, or hpop pump maybe is bad? Kind of odd for it to run absolutley fine then shut it off for a few minutes and now all these problems. dont think its bad fuel, the new fuel couldnt have go up to the engine that quick and the truck still had over 1/8 tank when i pulled in to refill. Ideas?