03 6.0 long crank runs bad at first HELP!!!

[cumminstroker]

Hi, I have a 03 6.0 that started acting up lately. I crank it for about 30 seconds before the oil pressure gage comes up on the dash and it takes a long time to start the longer it sits it is like the high pressure oil is bleeding off because when it does start it runs badly for a while like when you replace an hpop or injector o-rings. If I restart it soon after running it starts and runs good but the longer I wait the longer it takes to get oil pressure and the worse it runs after startup. I dont have any codes and I have over 1000psi ICP when cranking (once LOP builds pressure) Wondering if anyone has any input on what I should check first, thanks!