i think we have a real oil pressure gauge laying around our shop that is brand new. i will be putting that on this sat. what i think started the problem was when i got the truck the 2 grounds to the batt for fuel and ecu relays were disconnected and i was trying to figure out why the fuel pumps weren't turning on and trying to start it for a couple weeks. i i kept reading about these grounds that were supposed to be on there and werent... tucked under the batt tray. fixed em and my 1st ride around the block the pressure started dropping once motor and oil had time to warm up. before that, it was a work truck that sat for a couple years and was good when it was parked. i probably wiped the crank bearings out, but i wanna try everything else before i have to pull the motor. and no the motor doesnt knock. it also takes a few seconds more than i'm used to (compared to cars in general) build up oil pressure, if that means anything.