I bought my '01 Cherokee in april of this year. It has the 4.0 inline with just over 145 k miles on it.
At idle the oil pressure is +/- 60 psi and if I drive over 10 mph or faster the pressure guage will peg at 80 psi. I have no idea if it has the original stock oil pump or if it was replaced with a high volume pump. I have checked it with an under the hood manual test guage and those readings were right in line with the dash guage.
My questions are, is this pressure too high? What kinda damage will too high of oil pressure cause?
I know on Ford oil pumps there is a pressure relief hole in the pump that "vents" excess pressure back into the pan, is this true on my Jeep pump and could it be plugged or malfunctioning?

 

was the pressure always this high or did it just start

 

It was this high since I bought it.

 

Well My perssure is high too cause i replaced the oil pump with a mopar high volume oil pump. i did this cause i had almost 0 at idle and only 20 when running on highway. now its 50 at idle and about 65 on highway when oil is hot. but since i heard bad things about the fram orange oil filters otherwise known as the "orange cans of death" i swithced to mobil 1 filters and my pressure is down 10 psi 40 at idle about 55 highway.

 

bump

 

dont trust your pressure gauge right away. Rent or borrow a oil pressure gauge and verify it first.

 

Do you have a smaller oil filter on it? That can cause high oil pressure

 

Mine did the exact same thing. It was the oil; pressure sender. Replaced it and all is well..........