Not sure about a V6 in a 300E?
Anyway..........
Check out this thread and consider what Steve Brotherton had to say:
http://www.peachparts.com/shopforum/showthread.php?t=7045&highlight=fuel+distributor
You can also go to the SEARCH facility and use -> Fuel Distributor as the search phrase and select titles only. Lots to read, but you may find enough information to help you perhaps eliminate the FD as the problem.
It will require thorough diagnosis to resolve. No way you'll be able to quess-work this one. Doing so will result in many $$$ being spent shot-gunning new parts.