All of my MB diesels were/are sluggish when cold. PSFRED mentioned that late timing makes this problem worse, and I agree. However, we shouldn't forget that this low centane fuel we're getting is a long shot from what these cars need, and may be contributing to the sluggishness.

I have noticed that if I boost the centane about 4 numbers (from 42 to about 46), the sluggish time period is greatly reduced. So you might add a little power service if you haven't tried that. Checking the IP timing would also be a good thing if you haven't done it in a long while.

Joe