I have been searching all around the web for a reasonable cause, but couldn't find anything. Last summer I was having electrical issues, but the oil pressure gauge was reading dead center, barely any fluctuating. Then, the mechanic screwed a bunch of crap up and nearly destroyed it trying to fix a starting/stalling issue. But after he worked on it the mechanic started the vehicle and the oil pressure gauge soared to 60~80. I tried to ask what was up with the pressure, and he ignored the question. While running cold, it stays there, and most of the time while running hot. When accelerating, the oil pressure goes either a little bit down or a little bit up. The needle also seems very twitchy, and it has maxed out over 80 PSI a few times. I use Castrol Edge 10W-30, and get my oil changed every 3500 miles. 212,000 miles, 5.2L engine. Could this possibly be due to sludge, sensor or pump issues?
The oil pressure sending unit is a really cheap design and not very reliable. Rent or buy a mechanical gauge to check for any issues with the oil pressure. I've changed my sending unit 3 or 4 times over the years. When they are about to fail, they can give extremely high or low values or a twitchy needle. If the internal membrane (which is plastic or rubber) rupture, it will start leaking lots of oil.
If you replace the sensor I would get a Mopar. I bought an aftermarket one and barely tapped it while working and the top popped off. Holding the two in your hand, you can see the manufacturing differences.
Ok I'm having the same problem and I replaced the oil pressure sending unit on my 4.0 per advice I've searched on here but my gauge is still going crazy just as the original poster said yet my problem is persisting, any ideas? this occurs in conjunction with my jeep shuddering and feeling like it wants to die when I'm not pressing on the gas. really stumped and frustrated after I've replaced bad upstream O2 sensor re sealed both valve cover and oil pan.