Welcome to our friendly little club/forum Jeff.
When you say "just picked up" how many kilometres have you actually done yourself? Have you reset your trip computer (shouldn't have to disconnect battery to do this) The trip computer is only a rough indication anyway and as Craig has suggested 8.6 l/100 kms would not be considered bad for mainly short trips in an urban environment (for example)
The auto does obviously play a negative role in fuel economy, but so does hilly terrain, stop start traffic and short trips. Checking on carsales, the ADR figures (which are always optimistic) say 4.5 for "rural" and 7.5 for "urban" which is a wide variation compared to a lot of other cars. Driving style also plays a part. Is this your first diesel? Use the torque, not the revs and try and drive smoothly anticipating the traffic to reduce excessive braking and acceleration where you can.
There are heaps of discussions on here about this very topic and they all say much the same thing. The only way to get a true picture of your economy is to brim your tank, use a good proportion of the fuel then brim it again and do the calculations against distance covered. Doing this several times over weeks or even months, depending on how much driving you do will eventually give you a fairly accurate picture of your true economy.
The variation in feedback from owners on here (particularly for the Autos) is fairly varied. We ave a quite a few that do long road trips and the like that have boasted of low 5's or better and others who do mostly short stop start city commutes that grumble when they use close to twice that. Hope this helps a bit anyway.
Feel free to either browse the appropriate sections of the forum or use the search function to find more info or appropriate threads.
