Sometimes the revs just go way down when at idle, then they jump up for a second like to over compensate before setteling back to normal.

And my oil pressure seems to ge low at idle when running for a while (under 1) and it does go to 3 when accelarating but not instantly, the oil level is fine. Is this the normal behavior of the oil pressure or not?

These problems do not seem to be related, as the idle problems are pretty much random. and the oil pressure is after runing for at least 20 minutes

Regarding your oil pressure, the most common reason for the oil pressure to be low in a benz is the wrong oil filter. Make sure you have the correct oil filter for the car. Engines with higher mileage sometimes have low oil pressure, your low idle will also cause the oil pressure to be low as well. If it is pegging at 3 while driving you are more than likely ok. Just make sure you have the MB filter.
Regarding your idle problem, that sounds like a vacuum leak. What happens is that when your engine goes down to idle and there is air leaking in from somewhere, the idle will drop below normal, then the throttle control will kick in to compensate. Check all your vacuum lines as this is pretty common.
The 94 model had the wiring harness issues, if you have not addressed that be sure to do so. The harness could cause those problems as well as many others in the future. The harness is easy to replace, plug and play. Good luck!

Brian

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Brian W. Heitman

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