i have a 92 sonoma i bought as a project truck. the motor has recently been rebuilt but the oil pressure drops as it warms up. After about 10 minutes its almost on the redline. i've already replaced the sending unit, and oil pump, added a mechanical gauge in addition to the factory gauge, went to a thicker oil, retorqued all the bearing caps, and im still having no luck with this. what else is there to do to fix it or should i just ignore it? it doesnt knock and as soon as i hit the gas, the pressure goes back up but this is drivin me up a wall. how do i make it stop acting up?

The maual gauge is reading no pressure either?

What type of oil filter are you using?

yeah. the manual gauge shows 0 maybe 1 lb of pressure and the factory gauge completely bottoms out and the check engine light comes on. it dont do it till it gets warm tho. and its a fram oil filter.

If both the manual and the dash gauge are showing that and you've replaced the oil sender, more than likely 1 of your lifters has collapse, pull and inspect. They will not always tick if one is bad... A completely collapsed lifter will not tick at all.

good point, a loss of pressure this bad means no restriction in the system, or the oil pump is shot.