i have a 1998 jeep cherokee 4.0 inline 6. when the jeep is cold the oil pressure reads normal then when it heats up and im at idle it drops to zero then i give it gas it goes to normal. If i have my foot on the gas idling at a grand its fine. soon as i take my foot off it will drop to 0 and check gauges light will come on. wondering if any of yall had this problem. Thanks for the help.

Very common issue for many of us. Get your hands on a mechanical oil pressure test gauge and check it that way before you do anything else. Let us know what you find out.

mine would go full scale high. i pulled the sender connector and wiggled it back on.
its good since, contact trouble.

That doesn't mean you know the correct oil pressure in the motor; it just means you have a properly functioning electrical circuit from the sender to the gauge.

Yes, you still need to do a proper pressure check as well. The sending units are not k own for being real accurate anyways.
OP, you can pick up a oil pressure tester from Harbor Freight for around 12 bucks to do this test.

I also have a 98 with the same issue. I changed my oil to rotella 15w40 and added a quart of Lucas Oil Stabilizer hoping to help with

the problem,
Unfortunately, I hooked up a mechanical gauge and at hot idle it is still only reading 3-4 psi...looks like an engine swap is in my near future, good luck with yours.

I haven't seen the Harbor Freight gauge, so can't comment on that other than to say HF isn't known for high quality.

You can get a Bosch mechanical gauge for under 20 bucks at most auto parts stores. I got mine from Pep Boys for $16, had it installed and a trustworthy pressure reading in less than 10 minutes. It's easy, it's accurate, and it's peace of mind.

By the way, when I say, "installed", I don't mean in the dash. Just temporarily connected in place of the original sending unit, so I could read the pressure.

I have one. It's actually a pretty good kit. It has a six foot hose so you can drape it across where you can see it while sitting in the driver's seat.

i drove it home in oct, the gauges looked normal. comments here told me they were 'normal" i trusted them as ok.
about 6 months later the oil went full scale and i did as i said. the reading is the same as it was in oct. im ok with that.
i could question every gauge reading, but i wont.