I have a totaly stock 97 4x4 135,000 mi. well cared for and last night I noticed that the oil pressure gauge showing in the red right at 0 psi. so I let off the throttle to pull over and check things out and the gauge shot up to 40psi. so I put the truck in neutral and pressed the throttle slowly and at about 1475 the pressure starts to drop off, and at 1500 rpm the pressure shows 0.
Any ideas I am full of oil, maybe a bad sender.
Thanks, Mike
P.S. at idle I have 40 psi.