Have Mercedes Questions? Ask a Mechanic for Answers ASAP
I am sorry that you have not been helped yet. I just came online and saw your question
When you say idling rough, do you mean going up and down erratically or more like an engine misfire?
If idling up and down erratically, we need to first check for any vacuum lines that may have cracks or splits in them. When it is idling up and down, spray each one with some carb cleaner. If the idle smooths out when one is sprayed, that is your culprit and needs to be replaced.
If it is more like a misfire, let me know