installed a fass titanium 150 on my 99 cummins 5 years ago never have has a problem ever I swear by them

Just brainstorming here but might have your filters backwards or not tight enough?

OK I dropped tank found no problem all looks good in tank, supprised to see tank so clean inside. Filled tank with fuel. Got pressure gauge yesterday, installed it this morning, still has an issue cranking, have to let turn over several several times to crank at times, not all time but some. when at idle I have 22 psi on gauge, when going down road I have 21 smooth psi. very good seems to have plenty of fuel. just wants to be stubborn cranking at times. oh and when I shut truck off fuel pressure drops back to 0, is this normal?