OK,the car has more problems than just this but this one is the only problem I have had no luck in figuring out.The M103 is known for stripped cam cap bolts and mine is no exception.I just heli-coiled half of them and replaced all the lifters.The metal brace that runs along the top of all the caps is the only thing that was holding the lifters from going straight thru the valve cover.There were indentations on the inside of the valve cover.So now that the motor sounds like an inline six again and not a diesel the hesitation and cold starts are the next thingI need to fix.I'm an ASE certified tech but I've never owned a Benz of anything German for that matter.I noticed that when it's running crappy the diaphram that goes up and down in the throttle body does not open and close by pressing the gas pedal of pressing the linkage.You have to get under the hood and manually push down on the piece in the throttle body while also pressing the gas or the throttle linkage under the hood.If you just try to rev the motor by pressing the gas pedal it just stalls out.I'm guessin there could be an issue with that unit but I'm not a seasoned MB tech.Any info would be very helpfull.I just purchased the Mercedes Benz ownersBible.It's been helpfull and a lot of the problems I've encountered have been in the book.But there are several causes that could be the one.Thanks!