09 Ram oil pressure dropping off

My 09 ram with a 5.7 is having oil pressure drop off all the way to zero as soon
as the engine warms up. when the pressure drops I shut the truck off and let it
sit for a moment, then restart it and the pressure will come back up for a
minute or so.. then drop back to zero. Over the weekend I thought there was a
chance the oil pump screen was potentially plugged. I used engine flush this
weekend with 3 different oil changes hoping it would clear the blockage. this
worked for about 2 trips into town and now its doing the same thing again. I
Picked a new oil pump, screen/sump and gasket/windage tray. does anybody
have any other ideas before I try to figure out how to change this stuff out
without lifting the engine? also, if you know of any places I can get directions
on how to do this I would be grateful.

thank you