Fuel Economy and diff ratio

[RAEME]

Shite!!!! Not that high, mate 3.08 is your friend.

[utevanwgn]

Check your dif ratio , 2750 seems too low for 3.36 and auto.
The 253 seems over geared and having to work too hard to make the power to run at 100k, Ie seems you have to put the boot into it too much.
Almost as bad as revving to 4000 to do 100k.
However Your not going to get 100k out of 10L either.
cheers