The Italian-Tuneup comes to mind here. There's many ways you can clear the carbon out. You can...
A) Find a nice long 6-8% upgrade, and just floor it to downshift to 3rd gear, and let it run high RPMS for those few minutes, and if you do this at night, you may see glowing specks of carbon flying behind you coming out of the tailpipe.
B) Just flooring it to get on the freeway, or pull out into traffic on a busy highway until you reach your cruising speed (35-whatever m.p.h) works just as well.
C) I did this last week in the 300D, I found a nice long stretch of nearly empty highway, late at night, and just floored it until I couldn't go any faster. My smoke has been reduced greatly.
D) Use a diesel additive such as Redline, or PowerService.
E) Run some LubroMoly Diesel Purge through the injectors.
F) Use a full synthetic motor oil.
I've done all of the above, and everything runs great.
-Joe