Okay everyone, the reason is ULSD. Ultra low surfur diesel. Its a new standard where you can only have like 5 parts per million and we used to have 50, whereas Europe had 15 or something like that, so our diesel fuel standards are more strict than Europe's.

This is why there is a new 6.4 Powerstroke, 6.6 Duramax, and 6.7 Cummins. 2007 there was a temporary hiatus for VW's diesels, though I think Merc's CDI diesels with BluTec were able to pass. VW diesels will return in 2008 with BluTec as well; BMW will have their 3.0 TTD in the X series (not sure if X3, X5 or both) in 2008, as well as the 1 series arriving on U.S. shores (135i on the way) though I dunno if they will have a diesel at launch, I doubt it. Mini might bring over their diesels soon too