Originally Posted by 
gavinwibrow
				
			 
			For what it's worth, I've just driven from Wangarattta to Sydney, then back to Perth via the southern coastline (5,800 km) in my just acquired MY04 D2 TD5 auto - 2 people plus luggage and a couple of extra parcels.  
Except for one section, I made a concious decision to travel at 100 kmph rather than 110.  Much of this was on cruise control with a/c on to keep SWMBO happy.
The 500 km test section done at 110 kmph between Pt Wakefield and Pt Lincoln (cruise control, rolling hills plus a/c) resulted in 11.2 L/100 km or 25 mpg.
Best section was Albury to Sydney sitting on 95 kmph on the Hume Highway and no cruise control or a/c resulting in 8.5 L/100 km or 33 mpg.
Average fuel consumption for the total trip was 9.7L/100 km or 28.8 mpg (includes best and worst).  If anyone wants more info happy to oblige.