So I have a 2001 XJ that has had an oil pressure issue for some time. I have changed the sender twice and the oil pump. It runs around 30-40 psi while driving and then after driving for over twenty minutes or so it will drop to 0 at a standstill. Well I just changed the oil from synthetic 10w-30 back to conventional 10w-40 and busted the oil sender in the process (Typical I know......idiot!) So I'm driving to work today with the connector plugged into the electrical part of the switch that is disconnected from the actual mechanical part of the sender. As I drive down the road it is expectedly at 0 with the check guages light on, but at a stop, after warmed up, it fluctuates between 0 and 10. Now I know I need to check it with a mechanical guage, which I will do and give an update, but I just thought I'd see if anyone had any thoughts? Thanks Guys!

Try this before you give up! 20/50 oil, a NAPA Gold filter and a pint of "Motor Honey" additive. This worked for me. Brought my Zero pressure at hot idle up to 20 lbs. Best of luck!

Whats the mileage on the motor? Usually poor oil pressure is an indication of worn out/bad engine bearings. But 30-40 psi driving sounds about right

Thanks for the response guys! It has 120K and I looked at the rear main bearing while I was in the oil pan and it looked okay, not marred or anything, so I left them alone. But, yeah that was my fear was that my bearings were bad. I'm not tearing into this thing again though.