Just bought this 2 months ago, owned an 79 300D, so this is my first experience with a gasoline Benz.

After driving for about 4 weeks, and having some repairs done to get it through emissions testing, the engine started missing. The car had been sitting for about 18 months with occassional startups to keep everything going. The plugs were old and the air filter was bad, so I took it for a tuneup and oil change / lube. Pricey enough, but it did not cure the missing on 2 cylinders. I took it back to the mechanic, told him I was not happy with the results and he tinkered a bit, gave me a set of used spark plug wires off an old vehicle, tested that the wires were passing current and said he would think about what is causing problem. It runs like a pig, no power at all, lousy gas milage.

He seems honest and is recommended on this site for mechanics. He now says it is just a process of elimination to find the problem, could be catalytic converter, manifold vacuum, or fuel distributor. (Then he told me that a fuel distributor runs about $2600 new and that the used one he had would be much less. I looked them up online and found a new one that appeared to be the right one for $450, kind of hurts his credibility) I have run gas treatment through it twice and am not going to go the route of having a mechanic try one thing then another then another, my experience has taught me that is a quick way to lose a few thousand dollars.

Any one got any DIY suggestions? I am ok working on cars, but am unfamiliar with this one and need a lot of direction.