Well I'm on my second Aveo. My 2004 was a stick shift base model with no AC and sadly I did no fuel mileage tracking. I bought an 08 Aveo5 fully loaded with the 15 inch wheels, auto trans and AC. It now has 92,000km on it and I have tracked mileage religiuosly. I drive an almost 50/50 mix of city and hwy and get between 9.4 and 9.8 L/100km. Even on 100% hwy tanks its 9.4 but my hwy speed is 115km/hr. I have recently switched to non ethanol fuel and will see if that helps. Unfortunately I had to switch to premium to get non ethanol.