I got 41.5 MPG (5.67L/100km) once in my 2005 Automatic Aveo

[ontarian_frog]

I drove from Timmins, ON to Mont-Laurier, QC and averaged 42mpg. I wanted to see how good the car was when you babied it. The rest of the way to Moncton, NB, I averaged about 37mpg, with a stretch between Edmunston, NB to Moncton, NB where I averaged 32mpg.

Average speeds were

Timmins to Mont-Laurier: 90kph (56mph) That was about 630km (394 miles) on one tank (I did put 42L (11gal.) in).
Mont-Laurier to Edmunston: 100kph (62mph)
Edmunston to Moncton: 135kph (84mph) I love NB highways. 110kph posted limit.