My 92 Dak with 3.9L V6 has been mysteriously "using" oil lately. I say "using" because I can't figure out where it goes. No obvious leaks or dripping on the garage flooror driveway. Over the past 2 weeks I've had to add over 6 quarts of oil. It doesn't smoke or give me any problems, but the oil pressure gauge needle will bounce around when the level is low. When idling the pressure shows low on the gauge, but when I rev up the needle will spike high. every once in a while the oil light will actually come on. That's when I check and see that it is a couple of quarts low.

I've read some other posts that mention oil pumps and oil pressure sending units. Would any of these account for the loss of oil under normal running conditions? Especially where there is no obvious sign of oil leaking?

 

You may have a bad oil pressure switch, But as far of using oil. The bottom pan on the intake manifold is leaking pass the gasket and going out the exhaust pipe. Just look down inside the throttle body and you may see oil inside.