The problem started a few weeks ago. Could it be the electronic gas petal again. Just had it replaced a year or so ago. I suppose it could be many things. The problem has been intermiten for a few weeks. It seemed to have gotten a lot worse since I left the key in it and the battery went dead. Any help would be appreciated.

Eric Lockhart

 

Why exactly did the battery go dead, are you sure your alternator and related electrics are in perfect working order.....S classes have (or are meant to) high capacity batteries so I would not expect your battery to go dead quickly if you just left the key in the ignition?

Does the engine cut out if you put the autobox into "Limp home mode" (assuming your newer S-Class has this feature), and take the engine to over 3000RPM?

One interesting test would be to get up to speed on a safe empty road, have autobox into Drive, drive along and set cruise control on, then move the gear selector down to 4, then 3 and see how high you can get the engine RPMs. I'm not sure about 1999-to date S-Classes but in the older ones you could actually shift down a gear and the cruise control would not disengage if you have winter mode selected.....if this works fine...maybe its your gas pedal?

If the above doesn't work....set your autobox to 2nd gear, and engage cruise and increase the cruise speed to take up the engine revs. See if that works, if your engine doesn't missfire doing this above 3000rpm, it implies it could be something to do with your gas pedal...

If it does keep cutting out, at least you will have some useful info for your local garage about all the situations it cuts out to allow them to pinpoint the problem even quicker......