Oil pressure issue

[OBS_Build]

1996 k1500 with a 5.7, unknown miles on the motor. With 10-40 at operating temperature idles around 20psi. As I backed out of my driveway tonight gauge dipped to 0 and then jumped back up, oil looks good. I know the gauges have a tendency to be inaccurate, could it be the pressure sensor?

 

[GM01]

I had a few issues with oil pressure gauge jumping around when idle after warming up, replacing both sensors(one behind distributor and one underneath the car, near the bell housing). Your problem isn't quite the same as mine but I'd suggest replacing those sensors just so you can rely on them and be certain your oil pressure actually is dipping. Are you having issues with other gauges too? If so, may be an issue with the cluster.

 

[mason916]

1996 k1500 with a 5.7, unknown miles on the motor. With 10-40 at operating temperature idles around 20psi. As I backed out of my driveway tonight gauge dipped to 0 and then jumped back up, oil looks good. I know the gauges have a tendency to be inaccurate, could it be the pressure sensor?

I just got done dealing with this myself. mine ended up being a small leak in the fitting for the sending unit next to the dstributor. turned into a nightmare when i was tightening the new sensor and the brass fitting broke off flush with the block. its a sh*t show of a job but not hard just annoying. hope you have better luck than i did if thats your problem

 

[454cid]

Unplug the sensor and/or wiggle wires while someone watches the gauge. Check the number of pins it uses, as you may need that info if/when you buy another one.

My gauge moved around at steady RPM, and was getting worse. It never went to zero, but would dip lower than normal suddenly. Then started drifting right before I replaced it. After replacement, all is fine.

I don't have the brass fitting, but I have a Vortec 454. I'm not sure if the brass fitting is a small block thing, or a TBI thing.

 

[Schurkey]

could it be the pressure sensor?

Yes.

It could also be the wire harness, the dash gauge, or the power supply for the gauge.

It could also be an engine with crappy oil pressure--a worn pump, blockage in the pump pickup screen, etc.

I'd verify oil pressure with a known-accurate "shop gauge"; and if all is well, hope that the sending unit is defective. That's probably the simplest repair.

My '88 has gone through a series of dash-gauge oil pressure sending units, but what is on that truck is a totally-different part than what's on your, newer vehicle.