Most people will tell you to move the suspected coil, to fire the OTHER TWO cylinders.
If the misfire code moves with the coil, it would verify your suspicion ( defective coil ).
Have you looked at these ? ( Coil connectors ):
http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1R510G7PR1SL168HQF&year=1998&make=MB&model=C-230-001&category=F&part=Spark+Plug+Connector

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2007 C 230 Sport.