Well, well. I just got back from taking the car and really not much better off now than before. The plugs were indeed platinum and he changed them out to standard Bosch plugs. Its not missing nearly as bad now, but still is occasionally when it shifts and still is not idling completely smooth when in park.

He hooked it to machines, checked for vacuum leaks, etc. Seems as if the injector seals are indeed leaking (discovered by spraying brake cleaner?)- which he said it why it is still not smooth and why it is stalling in warm weather. Also, he said the thermostat needed changed (which I knew). I told him it was running very cool when cold and very warm when hot.

To check it and change the plugs was $90.00. I was thinking it was going to be $50., but it was worth it to find out what was going on and get the proper plugs in there and hopefully get better mpgs. He also noticed the noise that the valves/lifters were making on the passenger side of the engine- that, tick, tick, tick, sound. I also told him that it had a knock between 1500-1700 rpms and he said that the camshaft was likely worn, which I thought so, from the info I have gathered here. At first he said it could have a burnt valve because of it and causing the roughness, but when I returned, he did not mention it. He said it was the injector seals. I went back to pick up the car and he had made an estimate sheet. Seems as if it is going to be MUCH more to have this done there than I want to put into this car. $183. for the injector seals, $71. to replace the valve cover gaskets/INSPECT the camshaft/lifters/rockers and I think around $95. for the thermostat/gasket. He also said that the "engine electrical" checked out perfectly. He had some sort of huge "1980'ish" looking machine he hooked up to the car. I am assuming it was what they used back when these cars were new?

I spoke to my uncle, who has owned several Mercedes and he said that other than electrical, most anyone could/should be able to do this type of work on a older Mercedes themselves and recommeded the normal mechanic we normally use. I think he would do all of this for 1/2 the price.

If this does not work out (him being able to do it much cheaper), it may become more clear that I should just sell this car to someone that has the time/knowledge to put into this car. Everything else is fine.

Thanks again for all of the info you folks put in.