5.4 clicking noise /oil pressure drop

[Never Done]

I have a 2004 f150, driving home last night noticed loud clicking noise (propably the lash adjusters, typical for this engine) but then all of a sudden the oil pressure dropped to nothing. Shut engine off right away, started it again, oil pressure fine, drove farther noise came back then oil pressure dissappered again. i did this 4 times before getting it towed home. the noise i can understand but why no pressure, then pressure at restart. any help would be apprecieted. thanks

[LxMan1]

A partially clogged pick-up screen for the oil pump? Verify actual pressure with a Mechanical gauge.