Hi I'm having the same issue but mine oil pressure gauge goes up to h when I give it gas and drive it when I let off the gas the gauge goes back down to normal and I checked my oil and it fine.Hado. I had an issue like this a few months ago. It was my OIL PRESSURE SENSOR. It went out while driving down he road. I just happened to look down and it was pegged out past HIGH. I about freaked. I pulled off to the side and checked everything out, of course I found no issues at the time. I eventually drove it over to one of our firehouses in town and a friend of mine said that I only really needed to be concerned it it read LOW. I drove it home and later on after it had sat in the garage for about 4 hours I did a guage test to make sure the guage wasn't broken and all the guages worked fine. (I found a thread on here that shows how to do it) So I decided to just turn my key to the ACC position to see what kind of reading I got. IT went all the way past High. I knew than that I definately had a sensor problem b/c the engine wasn't running and it was reading HIGH????
I took it in and apparently it is a major issue with the 04 b/c the dealership didn't have one and they couldn't locate one at any dealership on the entire GUlf Coast. One dealership had one, but wouldn't let it go because they needed to have in case a customer came in with the isssue as well. I had to wait 2 weeks to get the part because it was on backorder. I drove around with it pegged out past H...took some getting used too!!!!
I got it fixed though and it's been fine since then. Hopefully this is what you are experiencing and not something major. It sounds like the same issue I had though.