the mpg computer will settle quite abit over time if you don't keep on resetting it though. was your passat the same? I mean did you work in the same environment?
resetting the mpg and seeing what it gives off?
If you think about, if you start fresh and then floor the truck like mad (i mean like you're stealing it), then you know you'll be dumping soo much fuel and you'll have an extreme bad mpg (i.e. 1MPG). Coast for awhile and that should go up to like 10 and then it'll level off at some number 15 (for example).
Now if you did the same to your Passat, if it is an exact instrument that calculates correctly, it should do the same. Floor it like mad and drive hard for 1/4 mi (that'll result in some ugly figures) and then coast for like 25 miles to give a more stable number.
If you look at the new rx330 (the new crossover lexus highlander vehicle), their mpg computer is crazy. I've seen that thing jump from 10-80mpg depending on how you drive during a 2 min window.
But overtime if you don't reset, the computer will factor in the average of what you've been driving along w/ the number of miles you've accumulated and it should give a more relative number that's closer to the actual.
But you know what, in the end, I don't care what the mpg says because I know I'm driving a quality truck that can go anywhere and not breakdown

Like I care what my mpg is... I know it's bad so there. If I need a better mpg vehicle, I'd get some hybrid or something that has as better mpg.
I think I've contributed my $0.99 worth here on this topic :50cal: