Looking at an 00xj 124k on it. Oil pressure at idle is about 25. When driving 35. Could the sensor just be crap or is the oil pump going. I hear a slight wrap but not bad. My zj knocks and has 279k.

 

If you have access to a mechanical pressure gauge, that will definitely answer your questions.
25 at idle is great, 35 at speed isn't awful, but I'd be more comfortable with 40+.
Could be the sender...only way to tell is screw in a mechanical gauge, or just replace the sender and see if things change.

 

Honestly I wouldn't even worry about 35psi even at driving speed. Unless your cruising speed equals greater than 3500 rpm. Rule of thumb for oil pressure is 10psi per 1000 rpm. My Jeep sits at 10psi at idle and between 25psi and 35psi at cruising speed and I'm completely ok with that

 

I have done a good bit of researching why year 2000 4.0 have low pressure. I have come to two conclusions:
1. Cracked heads contaminating oil and wiping out bearings
2. No solid explanation but low oil pressure is fairly common on 2000 models and people have driven hundreds of thousands of miles without a problem.

I have a 2004 GC with a 2000 engine with very low pressure (4PSI) that is a very busy daily driver with a lot of stop and go plus highway miles. My engine also has a slight rap ( I only hear it at idle). I have installed a mechanical gauge to reference and monitor....if pressure changes or if rap gets louder (hasn't changed in 8 months) I will pull pan and inspect. In your case you have excellent pressure,so if you are not losing coolant stop worrying! Oil pressure is more a condition than a function....as long as oil is delivered to the bearings and tappets with adequate FLOW it doesn't really matter if you have 4psi or 40 psi.

 

Just making sure it wasnt bad. My 97 has 42psi. I have a mech gage and on dash. Have 280k no prob. Just wanted something with less miles hahah.

 

If your not happy with 25psi I will trade engines with you. Ha,ha!!!