To be averaging that low an mpg is ridiculous in a TDI, even with 'town driving' and short journeys. Everyone is telling you they're getting far higher figures, with the same or similar engines and you're telling everyone you've calculated your own mpg. So that would insinuate to me (and others judging by their posts) that is something amiss.
Just as a point of reference I own a MKV Gti and every time I fill the tank up I reset the 'trip computer' and at the end of every tank (well mostly every tank
) I calculate my mpg and see what the average is. If I have done predominantly town driving and short journeys, including the odd obscene five minutes, then I usually see about 320-330 miles from a tank which is an average of 27.3mpg. On motorway journeys I have achieved anywhere between 400-420 miles from a tank, using a very light right foot and driving at a constant 70/80mph, which is an average of 33.9mpg.
What the mpg reads on short journeys at the end of a tank is irrelevant, because every time I stop and start the car the 'trip' resets itself. So in essence I could drive like a looney for a whole tank and then do one 'grandad' like drive at the end of the tank and the 'trip' at the end of that drive would read the last mpg figure (which could be as high 34.5mpg) and yet I may have only realised 290 miles from the full tank, meaning the true mpg would be 23.9mpg.
Whereas if I complete a continuous journey then the 'trip' never gets reset, so I can see if the 'trip' figure is realistic. From experience in most cases I can tell you that it is, for example after completing a recent very long motorway journey from Truro to Canterbury (330 miles) the 'trip' said I averaged 30.9mpg. I had used 49 litres during the journey, equating to an actual average of 30.6mpg. So 0.3mpg difference between the 'trip' figure and the calculated figure is pretty darn close in my opinion.
I don't know whether or not GTI 'trips' are different to TDI 'trips'. But I doubt that they are that dissimilar.
