Thanks for all of that info.... since my 300SEL is kinda doing this its an interest to me as well. I also have the occasional sputter at idle and sometimes the idle will jump up when stopped in gear, etc, but its all unpredictable on my car... some days its fine and on my car, temperature dont seem to make any difference.

Its good to know that the fuel filter didnt make any difference, because I was going to change this on mine, but I dont see any need if its not going to help. My car gets excellent MPG, it gets 20-21 in town... pretty good I think.

You mention the EHA valve and at one time I thought mine was leaking, as I could smell gas a little under the hood, but never seen any gas leaks. SO STRANGE, but this started when I switched to non-ethanol gas.... it persisted for about two months, but I was told it was not a big deal... then the store where I bought gas stopped selling non-ethanol and whats so strange is that the gas smell went away and has never returned and thats been about 6 months ago... not even a whiff of gas from under the hood. I am not sure if it was just a coincidence though or not.

I am sure the uneven acceleration (surges) is not a major problem, but is kindof annoying to me. I was going to have it checked, but my car is for sale anyway and I will probably let the new owner address it and come down on the price a little.

Thanks again