What viscosity oil are you currently running?
Is the gauge reading 1/3 when the oil is both cold and hot?
Maybe chuck a known gauge on in place of the sender unit to be confident about the pressure under different conditions.
This would eliminate:
A dodgy sender
Possible poor electrical connection
A dodgy gauge
I agree as it's the easiest & quickest way of troubleshooting for a start. It seemed gauge level read just about the same regardless hot or cold conditions. To be honest I have nil clue of the existing oil viscosity as it already had it in by previous owner but it certainly could use a change now. Cheers
Edited by the red zed, 22 September 2016 - 08:44 PM.