Once I turn my truck on my oil gage automatically shoots straight up to 80 psi. If I turn turn the key forward without starting the vehicle it stays at 0 but once the truck is on it goes straight up to 80 and doesn't move while driving.
My car has 140000 miles.
My car has an automatic transmission.
This is a common sign of a failing oil pressure sensor. This is a small unit in the engine block that reads oil pressure inside the motor and relays this information to the vehicle’s computer as well as the oil pressure gauge. When this is not working it may cause the gauge to display intermittently incorrect readings, sometimes saying 0 pressure and sometimes max (in this case 80 psi) or sometimes it fluctuates erratically. When the engine not running it is normal for it to read 0 since the oil pressure is created by the engine running. To have this corrected, I would recommend having a certified professional from YourMechanic diagnose the odd oil gauge behavior and assist with repair.