Hi guys hope someone can give some advice on the issue we have . We have a 2011 Audi Q5 2.0 TDI 170 and the fuel economy is just terrible. For example I've just driven 25 miles at 60 mph and the average for the journey was 29 mpg. The fuel filter was replaced recently and it wasn't long serviced . Just wondered if anyone has any insight to what caught cause it to be so poor ? Also tracking has been done in the last 500 miles