Kevin, your oil pump is driven by a blade on the bottom of your distributor shaft which fits into a slotted shaft on the oil pump and the pump is just two gears spinning which act as a pump. A gear on the camshaft drives both the distributor and the pump.
The pickup screen might be plugged but if it was I would expect it to be uncommon for the pressure to come back up to normal...that is to say I would expect a plugged screen to cause a lower pressure constantly. Have you noticed oil leaking anywhere? An oil pump failing might cause this. Often if that's the case, oil pressure at idle will go pretty low.
Have you changed your oil recently and did you by any chance use a synthetic oil or thinner oil? That might be the case. Oil that is too thick can also cause this as it might take more effort for your pump to circulate it at startup, but I doubt it is cold in Joplin now.
Jon,
I have had some time to ponder on this, and here's what I was thinking. I bought this truck back in October and hadn't driven it a lot because I had a lot of brake work and other things to do in it.I belive the old gentleman I bought it from said he hadn't changed oil in quite some time so, I bought Valvoline VR1 and a new filter and channged the oil a while back. What I was just thinking is, I wonder if some sludge broke loose and is partially clogging the canister oil filter. The oil I used is 30W
Kevin
