I have an old 2004 Dakota with 4.7 engine. Other day I was sitting still idling and oil pressure dropped to zero and alarm came on. About the time I saw it, it jumped back up to normal. I checked the oil level and it was good. Drove home fine. I drove it maybe 15 miles next few days and fine.

Today it done it again as I was parking to go in the woods. Checked the oil again when I came out and all was well so I headed home.....about 10 miles. Stop sign and it dropped and came right back up again. On the way home it would drop and raise erratically. Checked the oil again and its about a quart to much?

I was hoping oil pressure sensor and was gonna manually check the pressure but with the high oil I guess something is clogged not letting oil pass? Any ideas what it could be? Where should I start? By the way, when pressure was dropping and raising, the truck never changed. I mean temp stayed fine, no knocking , no change at all but the gage. Its got almost 200,000 on it and its my third one. Getting hard to find any around that year that's worth fixing though. Thanks for any advice.......shane

The Chevy 5.3 sending unit has a screen thats prone to clogging (especially if changes aren't done on scheduke) and is a known issue causing your symptoms. Don't know on a dodge.
The fix on the Chevy is new unit or screen removal.

Had a 1998 dodge 1500 do the exact same thing, motor finally locked up. just assuming it was oil pump. never tore it down just pulled it and put another motor in.

Check the pressure with a manual guage if you have one, otherwise just put a new oil pressure sensor in it and see what happens. If the engine is worn to the point of losing all oil pressure, it's already done for anyways, so you'll only be out the cost of the sensor.

If you let it run for a few seconds, do you hear lifters start to tap? That would indicate low oil pressure.

My first guess is an intermittent bad connection between the pressure sensor and the computer (or manual pressure gauge).

Second guess would be gunk clogging the pick up screen in the oil pan that moves around and blocks flow once in a while. Shutting off the engine lets whatever it is fall off of the screen until the next time you hit a bump and it makes its way to the screen again.

Do

Those 4.7l are well known for bad oil pressure sending unit sensors. Don't get a discount auto store one go get a mopar one or you will be right back in the same boat. All my 4.7l in my jeeps have had this sensor replaced.

That sounds like an issue that needs a recall.

Yep, replace sending unit before you get too excited.

Normally goes between 150000 to 200000 in my experience with them motors. The 4.0l also has the same issue pop up have replaced many of them as well. I'm sure everybody's I've replaced would of loved it to be a recall. Part is not expensive or hard to replace on either motor.

Would the sending unit somehow cause oil level to be high? Seems like something would have to clog or filter bypassed to raise the level? I’m no mechanic and I’ll will take y’all’s advice. The sensor would be easy and quick and I’ll try to borrow a manual gauge as well. Thanks folks......shane

I'm not a mechanic but a sensor is just that a sensor. If the oil level is rising drain it and look for water which probably means a head gasket issue. The engine doesn't produce more oil so the volume has to be coming from somewhere.

If your oil level is increasing you have way bigger issues then a sensor. Sorry didn't catch the part in op that said oil level got higher. If it's milky looking one of your head gaskets went or both did. If it's not milky smell it. If it smells like gas your cylinders are getting washed out with gas time for a rebuild. Can always do a compression test on each cylinder. With 200000 miles anything under 120psi is a sign of severely worn out cylinder. The manual for that motor says 100psi is the lowest for high mileage but trust me anything under 120 it's time to be thinking what the truck or motor is worth to you as far as spending the cash to rebuild or replace.

I have seen spark plugs not firing for one reason of other let gas in crankcase.

Is there any ce codes? You should be able to turn your key from off to on 3 times the 3 rd time leave the key on and were your miles are on your gauges you will get your pcodes right them down.

Well I changed the oil and filter, put a new sensor in, and now back to normal. Been driving around a couples days and it sits where it always has. I have no idea why it was reading over full on dipstick? The oil I drained looked and smelled fine. I change the oil in my Dakota every time my good truck comes due but I don’t put but maybe a third of the miles on it. Always pour in 5 quarts and never add any in between changes. Maybe I was seeing things, I don’t know. But thanks all for the help......shane