Drain the oil,or check on cap.If it is too dirty use motor flush to clean the entire system.should the problem persist,remove oil pressure switch connect oil pressure gauge (special tool) to see the diffrence between cluster gauge and connected guage.
I just got off the phone with my dealer and then GM. Yes there is a problem with the cluster and GM is covering them up to 7 years 70,000 miles. What a bunch of crap. They admit there is a problem but said I was over the miles. Who in the hell drives 10,000 miles a year ? Not me and I'm sure not a lot of other people either, I'm guessing that is how they came up with that magic number to cover their a$$. No wonder GM is in trouble, my next SUV will be a Toyota !! I don't have the money right now to replace it, so dose anyone know if the oil pressure also has a light / buzzer that goes off if the pressure get's too low. I know vehicle's with out gauges just have lights / chimes. I'm going to just keep running it until I can maybe put a after marker one on/under the dash.