There seems to be a much wider variation of MPG amongst 2.0TDI owners even when they claim the same driving style...
Having watched this forum for a few years, I think there really is a fairly wide difference between cars of the same type being driven in the same way - seems to depend on the particular car you have....
Firstly - the DIS display can be widely inaccurate. Mine over-reads by 10-15% so even though it says I'm getting 50 on a good 420 mile motorway run, when I brim the tank at the end, its really only been 43 or 44.
Next - tyres - they can easily make a 10% difference between brands, before you start changing the pressures...
And I can see a marked difference between new tyres and worn tyres - again, I assume the rubber on new tyres "moves" a bit and increases rolling resistance because when I change tyres (for identical replacements) I get less MPG with the new tyres than when running on the worn old ones.
And then there's tyre pressures. My 2004 model says run at 33psi front and 30psi rear for 18" wheels. Later models have much higher recommended pressures - why? who knows - but if I up my pressures to match the latest recommended pressures I get much better MPG but the ride really deteriorates....
My DIS says that I've averaged 49.5mpg over 42000 miles and five years...
The spreadsheet that I've kept which I've updated after brimming every tankful says that I've really averaged 43.5mpg - and have spent £4,700 on fuel since I bought the car....
Worst tankful came out at 36mpg, best tankful averaged 51mpg - that's calculated accurately from brim to brim, not using the DIS....
