Definitely make sure you have spare fuel filters with you these days, the ULSD seems to be stirring up a fair amount of junk in the system. I drove back from NY to CO this weekend and was doing fine until about 200 miles from home, cruising 80-85 mph most of the way with no problems. After my last fill-up (in NE) I started to notice a little loss of power on the hills, but I decided to drive home instead of messing with it on the side of the road. By the time I got home, the car would barely exceed 75 on even a small hill (just about the same power as a 240D at this elevation). As I recall, I changed both fuel filters less than 20K miles ago. I need to change the filters this morning (and get a new spare). Hopefully, most of this stuff will get out of the system soon.