Years ago there were posters that could not get more than 25mpg no matter how they drove. One poster Had even purchased his 240d new and claimed it had always been that way.

At the same time many got 30mpg or a little better. I never established the reason for this differential.

I do suspect that the poor quality of the diesel fuel sold in north America does cost about 5 miles per gallon. Compared to the diesel sold in Europe. At the same time our fuel is a lot cheaper than theirs.