I'd go with everyone else that said oil psi sending unit. Might be able to rent a mechanical gauge from a parts house, so you can check psi. The sensor is cheap, but the job sucks with the engine in the truck. It's behind the intake manifold.

Seems like when stepper motors fail, it's more than one. Was that way for me anyway.

To answer your other question, you get the motors off eBay.

 

Well I got ahold of a sending unit cheaply enough. The hex size on the new one is 27 millimeters, which is the metric world's way of saying 1-1/16" (1.0625").
After work tonight I figured I'd give it a shot, only to find out the OEM sending unit is probably an even worse bastard size, somewhere between 1" and 1.0625", which means some horses'-*** made it what is likely 26 millimeters (1.0236"!?!?!)! What does it take to make things in normal sizes? That stupid-assed bastard.

 

Most auto stores sale a special socket for it. Its very tight fit next to the valley cover and a normal socket wont fit without taking that off.

 

Thanks, I guess I'm gonna have to call around to try to find one. Anyone know what size that would be?

 

i used the Lisle 13250 to remove the old sensor and install the new one.
oreillys carried it.

 

Its usually labeled "oil sensor socket"

 

There ten bucks at oriellys

 

I got one for about 11 bucks at the local NAPA on the way into work. It worked as advertised. Took the old one out, put the new one in, OP gauge is working fine.

 

Glad u figured it out!