Mine (2005 4/4) does go to "full" but drops quickly and when "empty" has about 15 ltrs left. On a hilly drive (i.e. everywhere near where I live in N Yorks!) it is all over the place and I have learnt to ignore it and go on distance instead. Getting about 37-40 mpg.
As the tank is not rectilinear in shape it would not be linear anyway - narrower at top than bottom so will go down very quickly when near full, and lack accuracy when near empty. So I'm content that it shows empty when over 1/4 full. Just as long as I remember when it started looking empty...haven't actually run out yet...
