Three things are needed to run, air, fuel and spark . Rarely is it a lack of air more often it's a lack of fuel or Spark both of which the RCM manages. But just to verify that it is not a crank position sensor problem caused by either being faulty or a bad connection reach down and unplug the CPS connector and spray with contact cleaner let it dry and then put a dab of Dielectric grease on it and reassemble. Next because it is such a common problem with Mercedes as well as the crossfire I would purchase a new RCM and send the old one to DJ let him refurbish it and when you get it back put it in the trunk for a spare. There are more detailed diagnostic methods available here on the forum but what I gave you was the condensed version.