Question Author
Thanks for your help, guys. I know the combined figure is around 47mpg (35mpg urban/58mpg extra-urban) but this is achieving nowhere near this.
Zacsmaster: We've run the tank down to the bottom of reserve, filled it to the brim (45l/9.89gallons), made a note of the volume of fuel displayed by the pump, reset the car's tripometer, and run it right down to empty again. We've done this repeatedly for 3 months, and each tank has averaged between 15-18mpg (eg. the first time we did this the tank took 43.8l (9.63gallons), and was right down at the bottom of its reserve again after 169.5 miles, which equals 17.6mpg).
My girlfriend uses her car mainly for shorter trips - to university and back through town centre traffic in a round-trip of about 12miles per day, and a few shorter trips in the evenings and weekends (to work and back) which equates to around 4 miles each time. So, in total, around 80 miles per week at the most. Working on the urban 35mpg published figure, she should be getting around 350 miles from each full tank - but at the moment she's getting more like 150-180 miles.
I've shown my VW dealers the figures - including fuel receipts as proof! - from the last 3 months, but they're adamant that the car is running fine.
Perhaps I should try another dealer?
The car is still under the warranty given by the dealer (the same dealer we've been to see), and they seem reluctant to do anything. I just wonder whether they'd be more willing to help if the car wasn't still under their warranty.
Thanks again for all of your help, it's really appreciated.
DonQ