I noticed a little while ago that I couldn't hold a consistent oil pressure, if I was on the gas, my oil pressure would go up to about 45 on the gauge but if I was off the gas it would drop to about 10-15 on the gauge. I replaced the oil sending unit and I still have the same problem.

 

I have two 2001 Cherokees. One had this exact problem. I R/R'd the oil sending unit, and it fixed it slightly, meaning the pressure was better. Also, I had to get another sending unit as the first one was bad out of the box.

Having said that, I finally put in a new oil pump. Wow! Now I have high pressure, over 55psi! The motor has 113k on it.

 

Oil pressure changing with rpm is normally. As long as you have 13psi at idles and about 10psi/thousand rpm. Check it with a mechanical gauge as well. The factory gauge is terribly inaccurate.

 

Not sure why everyone always thinks high pressure means high flow . OP oil pressure sounds normal.

 

That's normal oil pressure. Mine does the exact same thing and it has 266,000 on it right now.

 

Yup, normal on these. Mine does the same, always has.

 

Thanks for the responses, I just wasn't sure exactly what it was and if it was normal

 

Assuming the new sending unit is somewhat accurate (as accurate as the stock one can be that is), it also depends on what type of oil you're running and the ambient temperature. But as the others have said those pressures aren't terrible.

 

It's amazing how much different oils can effect pressure. Was running basic chevron supreme and about 15-20 psi idle. Now running chevron delo 400 and its closer to 25-30 psi idle. Both were 10w-30.

 

Yes, pressure does not mean a whole lot. An an engine can survive with only a few psi as long as it is getting proper FLOW. My 4.0 has survived for over 5 years and +50,000 miles on only 4 psi!