hey guys ran into a little issue lately. for some reason my oil pressure has decreased. it is a 99 cherokee with the 4.0. When i first start it up the gauge reads exactly half way when idling. When it warms up and is drivin around 2000rpms and warm its runnin about 1/4 on the gauge. the problem is when it idles warm it is on the first notch on the gauge and sometimes drops off and the "check gauge" light comes on. its idling a little low i thought but still dosnt seem to add up to me. when i give it a small rev to get rpms up to 1000 and over the oil pressure comes up enough to get the light off. anyone else have this problem before? or is it just the gauge giving out.
thanks any help would be great!
Kris

 

after doing research i came up with this. I went to check my gauge. i read to turn the vehicle into the ON position and unplug the sending unit and the gauge should go to maximum. WHen i did this it only went to 1/4 the way and drops back to 0. this saying that the problem rest in my gauge and wire and not the sending unit. can someone confirm this for me ? thanks
kris

 

Does anyone else have anything to add?

 

I have the same problem on my TJ 4.0 l. It is very random and very frustrating. I am going to be checking the guage & sending unit as well as doing a pressure test....if all that fails it's oil pump replacemnet time :(

 

the oil pressure gauge problem is very common and 99% of the time it's a sending unit problem ... i wouldn't worry about it too much. Even if u disconnect the sensor unit and try to reset it and it doesn't work you don't need to go out and by a new oil pump!! mine has been doing this for the past 2 years and my cherokee is running as good as new!!

 

My current Jeep and my last jeep always showed low pressure. Especially during idle. After an oil change pressure would be better for a while. Take it in to see if its your pump.

 

i won't worry about it, as a mechanic this is the last thing on my mind, these newer engines always have failed sensor and its not the end of the world!!! i have better things to put my money on!!!