I read this thread (https://www.cherokeeforum.com/f2/possible-causes-sudden-no-oil-pressure-207488/) and a few others and it has me leaning maybe toward needing a new sending unit but I'm still not sure because my situation is a little different than the others I've read. As a preface, I have 145k miles, have a Jeep Cherokee XJ 2000, I've been putting Shell Rotella T6 5w-40 in and changing about every 5k (2-3 months) and I've done 3 oil changes so far with that but this recent oil change (last weekend), I wasn't able to find the T6 anywhere because there having a massive shortage so I went with Pennzoil 5w-30 this time. Well, this morning (39 degrees outside) I started the jeep up, no problems, gauges fine, drove about 5 mins or so and then noticed the check gauges light came on and saw the oil pressure gauge was all the way at 0. Mind you, I'm going about 50 mph as I'm looking at a completely still needle at 0. I slow down thinking the engine is about to go kaboom and I put it in park in the middle of the road and turn it off, wait a sec, and turn it back on. Still no oil pressure at all. Literally just 0. I gotta get to work and I'm thinking that maybe it's just not reading correctly because why wouldn't I hear any noises or notice anything else if it's got no pressure at all, so I go ahead and keep driving. About 15 mins later I get to a gas station and think to check the dip stick and it reads just fine, normal level. Nice color still too. I start her back up and she builds up pressure normally and I drive away and it's consistently at about 40-50 psi when I go. Never dropped again. What's going on??

 

Could be the sending unit, the gauge, or a wire/connection problem.

 

Mine acted up just like that and it was the sender. Get a Mopar one as the cheapest option sucks. I went through three before one worked correctly.

 

Use 15w40 diesel motor oil with a Motorcraft FL1A filter.

 

2x
Do not buy a sending unit that isnt Mopar

 

You guys are on point!! I got off work a bit ago and after reading the replies I popped the hood and found the sending unit and sure enough it must have got bumped or something when I changed the oil filter out last weekend because it's all wobbly and looks broken. The connectors are still hanging on but I'm not sure I can make it work. Anyone have any experience with them breaking off like that? Lol. I need to get a better look in the morning, maybe see if I can take it off and mess with it, not sure yet

 

" it must have got bumped or something when I changed the oil filter "

you and about a zillion other 4.0 owners. You need to buy a new sender "messing with it" isn't going to help

 

LOL. You're right, I just don't wanna spend $70 if I don't absolutely have to