I do mostly city driving, have a very heavy foot, and a Stage 3 Stillen and still average 18mpg every time. The worst I have ever seen on my car was 14.8 and that was full-on racing with friends for almost the entire tank.

 

my '05 with 20k miles actually just hit 20.2 mpg in the city this week! that is a first and amazing to me. i was getting an average of 17-18mpg in the city for the longest time, and have seen as low as 15.5.

i have no idea why the last week was so much better. maybe the car feels bad i have to pay 3/gallon for gas, and is trying to help out.......

 

I just finished a roadtrip this past weekend, and averaged 25.8 mpg, cruising at an average speed of 75 mph.

I've got the 05 5AT Sedan.

 

I just put 1100 miles on my 04 5AT this weekend, and had 24.8 on the trip north, and 21.8 and 22.7 on the trip back. Driving 70-75 both ways. The trip back was into a 20-30 mph wind most of the way, helping explain the mileage.

note, both were mpg based on miles / gas purchased. The navi showed, as normal, a higher mpg.

 

I consistently get 23 mpg driving 50/50 hwy and city at 10 mph over the speed limits. I have an 05 5AT and drive it at WOT 6-7 times per tankful. This is exactly what my 01 Maxima SE Auto with overdrive got.