Myself and Tecodan were testing last night on the hume @ 110km/h

Mine being a 3lt auto, Dans being a 3.5lt Manual.

Myself - 6.1-7.0L/100km
Dan - 6.5-8.1L/100km

This was measured over a distance of 40km (I did not have cruise control, Dan did)

I was quite impressed with my figures, my guess is that it is a result of cleaning the throttle body and intake manifold out (removing the carbon buildup)