Oil Pressure irratic guage

My oil pressure guage will sometimes go up to over 80 psi and stay there on a trip of 300 miles or more then the next day show a normal reading of 45 psi and possiably stay there for a week or more - What’s going on ? 2004. Chevy Avalanche.

how many miles? Where are you? What oil do you use?

My guess would be a gauge problem.

How many miles on your current oil? Are you using an oil that meets the specifications in the car’s owner’s manual?