89 IROC 5.7. My oil pressure gauge is pegged all the way over to the right. I went ahead and changed out the gauge sensor located next to the oil filter and that did not fix it. I guess at this point it must be the gauge? Is there anything else it could be? How difficult is it to change the gauge?

 

Hawks has some cheap clusters and at this point I think its cheaper to get one from them (they even set your odometer) than try to fix yours if you are not good at this kind of stuffs. Problem is sooner or later we will need some form of tutorial to fix these things since these cars are become more rare. I also had this problem after I rebuilt an engine the thermostat crapped out and I overheated the engine ,got the temperature really high and the gauge needle moved past the red zone. The engine was fine ,turned off the car let it cool and changed the thermostat but the needle remained always abit to the right. I have no idea why this happens because I don't know how our gauges work. Also I went faster than 120mph with a car that had 120mph dash but this over the edge gauge thing is not present in the speedometer ,just the oil pressure and temp gauge.

 

The wire could be shorted to ground, the connector could have alot of crud in it also, the gauge is ohm's to ground.

The opposite issue some times occurs when you replace the sensor and put way too much sealant on it or tape and the sensor doesn't actually ground to the block.

Does it stay pegged with engine off? If you unplug the sensor lead and put an ohm meter on the wire what do you see? If you ohm out the sensor what do you see. I have more than once gotten a brand new bad sensor.