My gauge started going haywire about 4 years ago. After a few miles reading ok it went up off the scale.
It was a faulty oil pressure sender. The car is a 2002 4litre with Gems management and if the pressure is lost it cuts power to the fuel pump to stop the engine. There is a switch on the oil pump housing that will do this. The faulty sender was just for the gauge and replacing it put things back to normal. This sender for the gauge only and is accessed under the car driver’s side towards the rear of the engine. Simply disconnect the wiring, unscrew it and replace. There was no actual oil pressure loss as that would have cut the engine.
Have a look at Gomog and Plus8 specific section.
https://www.gomog.com/allmorgan/plus8index.html
