I think on that engine near the oil filter there is a vacuum line, I have knocked mine loose from the manifold twice now and my 96 sl320 did the same, would barely run, surging and jumping. I bet they knocked a vacuum line loose and that is what is causing your problem. Take a look near the oil filter and anywhere they have been and make sure you have no leaks. One that bad you could hear, start the engine and open the hood, you should hear the hissing sound. Good luck!

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Brian W. Heitman

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