Oil-pressure gauge always reads "5" Any idea why?

[no.radar]

Start the car, gauge reads "5." Turn it off, gauge returns to "0."

I know the gauge itself is working properly, so what do I replace next?

[vulcan300]

The oil pressure sender may have gone bad?

[Eagledriver]

The guage pegging high means you have an open circuit. Either a lose/broken wire or a sensor that has gone open inside. Easy to check. Just ground the wire at the sensor and the guage should drop to zero. If it doesn't, it's the wire.

[no.radar]

I figured it might be the sender, but the "open circuit" suggestion makes the most sense given some other minor electrical gremlins my tech is already trying to pin down.

Again, thanks for the quick responses.

Photo of car attached as a small token of my appreciation.

[Walt Fricke]

The most common open circuit is the connector being dislodged from the sender. If you have been pulling gauges out of the dash or otherwise messing around behind the dash, it could get disconnected on the gauge.

[Quicksilver]

Also check the wire right near the connector. Years of vibration where the wire flexes next to the connector can break down the wire inside and create an open circuit.

On mine I tested the wire a few inches up and it was good so I spliced on a new end section and I made sure I put a "service loop" at the end to help deal with vibration.

[bigel]

This is great diagnosis information, again this list and its members never disappoint.

My gauge almost pegs upon startup and gradually goes down while driving, but very slowly; I'm talking like over the course of an hour. Anyone with ideas about whether this is; a) normal, b) sign of a 'on its way out sender', c) something else?