how do you change a faulty sending unit on a 91 chevy S10 pickup on 1991 Chevrolet S10

not sure if the above is the solution. My check gauges light comes out at low idling and oil pressure stays in red zone but goes up at i accelarate. oil level is normal.

Asked by for the 1991 Chevrolet S10
I'm assuming to the oil gauge. Went to mechanic today and he told me that based on his experienced with S10 pickups it could be this faulty unit sending an inaccurate message to the oil gauge. Do you have any idea what they are talking about? I figured it must be a sensor or relay unit i'm presumed
You need to find a tech that will perform a oil pressure test with a direct feed oil pressure tester gauge.
i agree w/parts guy