I have a 1998 E320 sedan, yesterday it began shutting off intermittently, it just shuts off, the engine will crank but not fire. After about 20 minutes it will restart and may run 50 miles, or it may run 10 miles before it shuts off again. There is nothing in the message window indicating a problem. I am thinking it may possibly be a fuel pump relay, but I do not know where the relay is located. Any ideas would be greatly appreciated.
Regards,
Ray

I had the same probalm with my old E300 92 esp when the weather started to get warm i changed the overvoltage relay. some other relay too then the computer..then someone at mercedes told me that the for some reason the computer connections INSIDE the box meanin the printed circuits get loose .So i opened the first computer i had originally ,took both circuit board a part and reheated all te connections witha soldering iron..Guess what i drove that car for another 3 years and its stilll running.

Hi Ray, faulty crankshaft position sensors are a common cause for the problem you describe. They're cheap and easy to replace as well.