I have a '03 SLK230 with 54000 miles---the engine will start to "surge" or lope by about 250 RPM after an extended (5-10 miles) run at 70+ mph. If I shut off the engine, and restart, it will go away until the next time I have a higher speed run. It started doing this before, and after I replaced the air filter-and I've also cleaned the MAF sensor. Any ideas? Thanks, Larry

 

These cars are hard to know. Even with our 1993 600SEL, promised to be on the forward edge of technology at sell point (huge mega $$), after experience, my wife I know, we have to go with the flow and milk all we can get out of the technology. Issues = many. Problems = a lot.. We just deal with it, fix what we can in our own garages, ( I am a masters degree in auto engr'g and have owned a few MB's and BMWs).
Will reply with some tech insights. thanks..
Bill & Monika Mercer