Just two days ago I did 1.042 km with one tank (really filled to the brim). Average speed 82 km/h at about 2/3 Belgian AB ( 120 km/h max!:-) ) and 1/3 what you would call Landesstrasse (70 km/h max.). This is my absolute record sofar, I normally can do between 850-950 km with one tank.
Trendline 1.9 TDI DSG 5 seater, mod. 2006