OIL PRESSURE SENSOR REPLACE/REMOVE

Alright So I Recently Bought The Truck Listed Above, When I Bought It, I Noticed The Oil Pressure Gauge Was A At Zero I Asked The Seller...

My Gauge Was Fluctuating A Little At First But Now It Stays At 80 Psi. I Just Changed The Pressure Switch, But It Now Just Stays At 80 Even...

Changed Oil Pressure Sensor And Wiring That Plugs Into The Sensor. Now Every Time I Plug It In It Starts For 10-15 Seconds. They Stalls....

My Oil Pressure Gauge Fluctuates From No Pressure To High Pressure In Idle And When Driving. How Would I Come About Changing The Oil...