1992 Jeep cherokee inline six 4WD?

Inline 6 is a great engine evidenced by your 300000 miles on it. That is a lot of miles. Look first at getting a new oil pump.

Funny thing with these Cherokees. It not the pump, or the gauge. It's the thin, flexible tube that the pressurized oil is in, that gets clogged. That why it reads all over while you are going the same speed. However, 300,000 is a lot on an oil pump, this might be the problem. But the pump isn't going to speed up or slow down, it's going to be on OR off.

Hey, Are you experiencing any difficulty with the truck 's operation. If not, leave it alone. If it only had an idiot light, it would only flicker now and then, and you wouldn't even think about it. Agree with the person that said keep it full of clean oil.. I might even suggest you go to a heavier multi grade oil..ex: if you're now using 10W30 go to 10 W40. It's also possible that your dash oil guage is weak and tired. You can always do an oil pressure check right from the sending unit.

keep fresh oil in it. and think about a new oil pump. not a high pressure one go original replacement. high pressure will pump all oil to the top and leave nun for crank and piston rods.

sounds like your oil pump is tak'n dump or your bearings are so far gone that your pumpcan't keep up with it. With 307K on it I think u'v got your money's worth out of that motor.

that's a lot of miles. Congrats. may be time to invest in a rebuild. Otherwise, you're going to be accumulating time and expense replacing parts.