I have done plenty of searching and haven't revealed any answers so here it goes:
(1994, 4.0, 5 speed, 148,xx miles)

My Cherokee recently started to show high pressure, as in off the gauge, while I was around 2500 rpm. Sometimes it would come down when I would have the clutch in or in neutral. I didn't think much of it since there have been no other issues. I searched around and found out about the issues with the sending units and ordered one. Today I changed the oil because it was time and I was wondering if anything would change with the filter. I go and drive the Jeep about ~15 minutes and once it was warm it began to smoke. I stopped and took a look and I had a pretty quick and steady drip coming off the back of the engine. Its right over the exhaust and its dripping right on it and smoking badly. It has always had a super slow leak somewhere back there that kept the oil pan wet but not enough to drip on the driveway. I'm going to try and hook up a mechanical gauge and see what it shows and then possibly run some marvel mystery oil through it and see if I can get something to unclog. Maybe its just a coincidence that my oil pressure sender went out and I sprung a big leak at the same time...

Any other ideas or suggestions?

 

Off the charts high reading typically means the sending unit is shorting out somewhere (possibly internally in the sensor, possibly wiring.)

What brand filter did you use?

 

Last time it was a Puralator, this time its a Fram.

 

I had a suspicion that you'd say Fram. Get that orange can of death off your XJ immediately!

Get a WIX (my XJ really likes WIX, which is why I mention it), Napa gold (also a WIX) or another quality brand on there.

I would bet that it's the Fram that caused the excessive leaking. You may need to do your oil filter adapter o-rings and valve cover gasket.

 

I literally had high oil pressures right after an oil change and it was due to using a Fram. It was legitimately high (verified mechanically). The WIX filter cured it and my engine seemed to run smoother.

My engine is from a 94 XJ after the P.O blew up the original engine by running with no oil.

 

The pressure was there before the Fram but I will check that, hopefully that is where the leak is coming from. I am going to dig into it today and see what I can find.

 

X2, can the Fram and get a Napa gold/wix. There are a number of good reasons to do that. No idea on the high pressure unless the passage under the sender is plugged, or the wire is grounding........Watch for leaking from the oil filter adapter O rings, they all harden and leak, then it will blow back and drip from the bell housing on the pipe where it crosses over. The bypass valve in that orange can if siit shouldn't make the pressure higher. If you do do O rings look for the kit from Crown automotive

 

Finally had time to mess with it today. I went install my new sender and the old one was loose, as in I removed it with my hands, only a couple threads holding it in. I installed the new one and everything went back to normal. My guess is the sender came loose (somehow) and went bad, and that created the high oil pressure. Then I changed the oil and probably bumped it and caused the leak. Next time I change the oil I'll switch out to a different filter, never heard anything bad about Fram and I have been using them for long time.

 

The sender failing is what gave you the "off the chart" readings and it being loose would definitely cause a leak.