7.3 no start in mornings oil pressure

[BOTLDPONY]

i have been noticing that the last few weeks my truck will start and it takes about 5-7 seconds for the oil pressure to come up if i do not rev it up right on start up it will die and i have to crank the piss out of it then the oil pressure gauge moves up and then it fires up. i read somewhere that i needed to check the level of the hpop so i pulled the allen out and it was LOW i put about 4-5" of oil in it, cranked it and fired right up. what do you think the cause of this is? LPOP???

i am needing my truck so any help would be appreciated as i need to fix this asap. thanks!

[BOTLDPONY]

just went and tried to start it 2 hours after last run and still hard to start! seems like it is really bleeding off. now worse than ever! anyone think the IPR is bad? or a check valve stuck if so where is the check valve i have been researching looking for info on this and cannot find it!!! please please help this is my daily driver and need to fix it this weekend. when the truck does start runs great no problems at all.

dont know if it matters or not, went out and hopped on top of the engine and i can see a reman label on the hpop part number 449 so i dont know if this helps but just some more info.