1989 Plymouth Voyager oil presher

With that kind of mileage you probably just have a worn out engine. It's really not worth investing in at this point. It's already given a life's worth.

Hi wbouts. Welcome to the forum. Have you checked the oil level? Which engine do you have? With the 3.0L engine, 6 pounds of pressure at idle is acceptable and the sending unit is calibrated for that value. For the 3.3L, that is way too low. The 3.3L did have a lot of trouble with the sending units. The clue is the oil gauge reading will vary up and down while you're driving at a steady speed.

The place to start is by having the pressure checked with a mechanical gauge to find out if the problem is with the sending unit or in the engine. At the mileage you listed, you may have worn crankshaft and connecting rod bearings that are allowing excessive internal oil leakage. Ignoring them will lead to much bigger problems very soon. If the oil pressure is indeed low at idle but comes back up at higher engine speeds, you might get away with having those bearings replaced. I did that years ago on my '88 Grand Caravan with the 3.0L engine while looking for a different problem. It has 379,000 miles now. It only takes a couple of hours to replace those bearings when the vehicle is on a hoist.

Caradiodoc