When I come to a stop light my PSI drops from 50 driving to 20 idle. Has anyone used Mobile 1's oil? Any increase in PSI? Should I change to a higher weight? Like maybe a 10w40? (Keep in mind Im from Alabama, and the temp is about 100+ daily right now.)

 

How many miles are on your jeep? That doesn't sound bad I believe it's normal to see that kind of pressure from a high mile 4.0. These things are like tractor motors they just keep on plowing along. My pressure runs 40 at a real hot idle and 70 to 80 at high rpms. But I only have a couple thousand miles on a new crate motor so hard to compare. I run shell rotella.

 

113k

 

Mine stays between 45 and 25. 10w40 166k miles.

 

The book says 13 psi at idle and 37-75 above 1600 rpm so yours seems within specs. If you are unsure get a mechanical guage and check out the accuracy of your in dash guage.

 

Mine sits at like 70 when just idling.... is that bad?

 

Your sensor could be messed up.
It needs checked out for sure.

 

Bingo.

Oil pressure fluctuation is "normal" between idle and higher rpm.

If you are within the above specs, you are fine. And 20 psi at hot idle is not an issue whatsoever. My 99 has run at about 20 psi at hot idle since the day I drove it off the dealer's lot.

 

Yes I run Mobil 1. No increase in pressure. My oil pressure does exactly what yours does. I have 146k miles on mine.

 

Mine does the same.

 

Sweet. Thanks guys

 

Old rule: at least 10 psi per 1000 rpm's.
Actual standard: 5-6 psi per 1000 rpm's.
Also, you can find a climate chart in the O. Manual or online that give recommended weights vs. temps operated in.

 

Mine does 25-45 lbs. It has 102k on it, but it has always ran close to those figures.

 

Just got a little worried bc I have a friend with an 01 with 250k on his and he idles at 40

 

40 psi @ idle=Malfunctioning gauge or sensor.