I got advice the other day to "Italian-tune" my new-to-me 300 SDL when I mentioned that it smoked a little at full throttle.
I drove it to work yesterday and did just that: I floored it and ran it up to about 90 MPH on an long, uphill section of the highway on my way to work.
By the third time I did this, it not only no longer smoked, even at WOT, it seems to idle smoother and run quieter.
I got the advice from a serious MB Diesel owner who has five of them. He said they like to run hard and you need to do this pretty frequently to get all the carbon and soot out if it isn't driven on the freeway regulary.
Well, it is driven on the freeway daily, but it is in stop and go commute traffic I'm afraid. So, I'll be adding these "Italian tune-ups" to it's schedule every month.