i have a 96 jeep cherokee with the 4.0 .my oil pressure at sitting idle is 80 my question is what is causeing it to run this high

 

plugged PCV tube. get a coat hanger and run it through to clear any sludge, then spray in carb cleanerto clear it out more. (take off the truck first, no carb cleaning in the engine top)

 

That has nothing to do with oil pressure. Have you changed the oil recently? Could be a faulty sending unit or a clogged filter. The best way to tell what the actual pressure is would be to screw in a manual pressure gauge and see whats going on.

 

x2

 

mine always idles at 80 and just did an oil change and filter today and now it sits at 40 at idle and when im on the power it goes back up to 80

 

i was told to try the sending unit first.i bought it last month and havent drove it any cause ive been replaceing all the front bushings.but i will try and change the unit and also do a oil change.thanks

 

the sensor can fail either into closed or open, giving you either a max PSI reading or 0 PSI. If it doesnt move no matter what during driving, its most likely the sensor.

 

changed the sensor in mine last week...80 cold....60 warm....40 idol....232,000 miles...I'm happy with that.