Oil pressure skyrockets, then plummets

Well, the title was an exaggeration, but the other day I started my Jeep to go to work and it started and ran fine...then 2-3 miles down the freeway I look at my oil pressure and it is pegged to the top. I think, "oh $#!+" and throw it in neutral to see if it settles. No luck. Then I turn the ignition off in neutral and the start it back up. The pressure read normal from then on.

Is this a one-time deal? Is my sensor acting up? Should I get it checked?

Just wondering...this was 3 days ago, and there have been no symptoms or problems to speak of. Thanks!

could be an intermitent short to ground in the wiring. when you shut it off and then turned it back on, the movement of the engine may have removed the short...for now.

Pull the sender connector apart and clean it, the senders do go bad which is why most parts stores carry them in stock...Just make sure you get one for a gauge and not an idiot light at least on a 96 or older, my 98 uses the same sender for both gauge and idiot light, I replaced my idiot light dash with a gauge dash out of a TJ, dropped right in.

Well, now...much belated...I have an update and another request for advice. There had been no problems with the oil pressure for weeks now.

But...Tonight I started up the Jeep and started driving home from work on the freeway. The oil pressure was suddlenly pegged at 80. I tried turning the engine off and on again, but it kept up. I pulled over at a gas station and checked the oil, and it was right on and pretty clear (thank you Mobil 1). I started it up again and drove home, noticing that it would hover around 25 when idling in neutral or park, and about 45-50 when idling through 35mph, then rise a bit to near 60 or 70 when under acceleration.

There has been nothing to alert me to check the engine or an oil light--just my guage showing it pegged at 80 for a bit, then blah blah...as stated above. Engine runs smooth, I follow LOF schedules, have performed a tune up, and don't beat the crap out of the engine. Auto, i6, 80,000 miles on a 2000XJ.

Any thoughts?

Depends on what you did IRT our previous recommendations of cleaning the contacts/plug and/or replacing the sender unit... next comes a mechanical gauge snaked back into the cab...

There are usually only three reasons why the oil pressure gauge gets pegged at the high end with the engine running and these are:

1. Bad gauge sending unit (most common).
2. Gauge sending unit wire grounded.
3. Oil pressure relief valve inside oil pump is stuck closed.

You can differentiate between the first two and the third by installing a mechanical gauge. A normal oil pressure reading will rule out no.3. If you install a new sending unit and the reading returns to normal, that'll also rule out no.2.

Thanks for the help...again. So for a mechanical gomer such as myself, where does one locate the sending unit, and how much of a nuiscence is it to do myself?

The sending unit is a black cigar-shaped item that sits above the oil filter. It has a single-wire connector attached to it. Use a 27mm wrench to unscrew it from the elbow above the oil filter adapter. It'll take you no more than a couple of minutes so it's a piece of cake.