I have an 05 GMC LLY when I turn the truck off the oil pressure gauge will stay at 60 and when i turn it back on it will shoot up to 120 and bury the needle when i drive. Im hoping this is just a faulty gauge. Does any one have any suggestions?
Replace the stepper motor in the cluster. This is a very common problem. I just fixed my oil pressure and speedo last night. Both started out doing what you described before both were locked all the way around to the right on the bezels.