Hi,
This could be a couple of different things such as a bad sensor or even the instrument cluster.
Let's try a couple of things. First, locate the oil pressure sending unit on the back side of the engine behind the intake manifold. See pic 1 for location. Disconnect the sensor and see how the gauge reacts.
If there is no change, I need you to check pin 1 in the harness connector for continuity to ground. Also, pin 2 in the same connector should provide a 5v reference signal with the key on. Check that as well. See picture 2 below for pin orientation.
Here is a link you may find helpful when testing the wiring:
https://www.2carpros.com/articles/how-to-check-wiring
Let me know what you find or if you have other questions.
Take care,
Joe
See pics below.
Images (Click to make bigger)
Friday, November 26th, 2021 AT 10:59 PM