When you turn the key to on the oil pressure gauge goes to high and stay there?

If the oil pressure gauge pegs to high when you turn the key to the "on" position, it could indicate a malfunction in the gauge itself, a wiring issue, or a problem with the oil pressure sending unit. It's also possible that there is an actual oil pressure issue, but this is less common when the engine is not running. To diagnose the problem, check the wiring and connections, and consider having the oil pressure tested manually with a mechanical gauge for accuracy. If the issue persists, consulting a professional mechanic is advisable.