Regarding the 1994 E420, is it late 1994 model or early?? I believe E420s also have the management changed. Correct me if I am wrong....
I have my car serviced only at Mercedes Dealers, and have Mercedes do what they have to do. That's why I suspect that the problem is with the tuning. Since late-1994+ have different managements, maybe it will have different tuning specs, too.
P.S. I have coolant(50/50 as factory recommended) changed every 2 year and oil changed every 3000 KM or every season changes(summer-winter, winter-summer).
[This message has been edited by akry (edited 09-10-1999).]