I have a 1996 jeep cherokee country and when I bought it back in may and it ran fine but needed some work so since then I replaced the radiator, fans, Thermostat, Thermostat housing, water pump, because it was full of rust from sitting for basically 5 years then I replaced the battery and swapped the trans filter and atf just to give some back story if I'm missing something then my check engine light came on for the cps or pickup in the distributor so I replaced all of it instead of just the sensors because the distributor cap was full of rust and worn down and the shaft of the distributor had quite a bit of play so I got a new distributor and no matter what i did it was always 2mm off the bolt hole so I couldn't get it lined up without being out of time and running rough so I ended up talking to the parts guy for the jeep dealership in my town and he said there were 2 distributors for the 96 but it's based on the manufacture date so I ordered the one he said would work and got it installed TDC all lined up exactly with the oil pump at 11 followed all the instructions from every distributor forum I could find and my chiltons book thought I was all good went to fire it up and immediate oil pressure at 60+ and from what I could tell definite misfire but not like a ping like it's out of time from the first distributor


This is the one that I couldn't get to line up

https://www.napaonline.com/en/p/NNDNNDST4696

This is the one in it now

https://www.napaonline.com/en/p/NRD484694

and this is the oil and filter I used 6 quarts 10 w 30 mobile 1 full synthetic and a napa gold filter


some other forums said it could cause issues I guess I'm not sure

There's absolutely nothing wrong with 60psi oil pressure at cold start up..be happy. Move on to the misfire.
I assume you changed the plugs, plug wires, did all the grounds.

Throw away the Chilton book and download a Chrysler shop manual

Even though the previous oil pressure was 20? When I got it already had newer plug wires and plugs and i did not replace the grounds just made sure they had good contact and were clean

Your oil pressure sender is likely failed. No worries.

Plugs, wires, cap and rotor every 30,000 miles.
Ever cleaned your throttle body and IAC?
Made sure your intake manifold bolts aren't loose?

That's maintenance stuff to verify first.

after that, better test the fuel pressure.

OP
1) what oil and filter did you have in it before the recent change when the pressure reading changed?

2) take a look at the oil pressure sensor and the connector to see if you may have wacked it when you changed the filter.

While it's entirely possible the sender decided to take a dump at the exact moment you changed the oil it wouldn't be my first guess