I just finished my first tank of post break-in city miles.

According the the trip computer, I got 20.9mpg and averaged 32.6mph. I commute about 10-miles each way to work which takes about 15-20 min in light traffic, with a little more than half that distance on the freeway.

One thing I noticed that seemed strange, is that the average milage display never changed in just a 1/10th increment. The display shows XX.X precision, but jumps up or down in 0.2 or 0.3 mpg increments. During most of my driving the past week, it moved around from from 20.4 to 20.6 to 20.9 to 21.1, up and down the same intervals.

/2007 G35 Sedan 6MT, Premium, Nav, Active Steering

 

How many miles do you have on your car? More importantly, how many miles have you put on the car since your last reset? Averages can seem funny because it will average 0 mpg if your sitting at a light or stop sign. I'm guessing the display will jump less the more miles you have. Try a few more tanks without resetting and I'll bet it will slowly change afterwards.

 

(doh! I spell checked "mileage" before posting this time)

Well, sitting at a stop-light, I would expect the real-time mileage to show 0. My Average Mileage doesn't go to 0 when I stop.

I reset the mileage each time I fill the car up. The fuel economy display shows the history of the previous 5 or so tank-fulls. I usually go around 300-350 miles between filling up (and resetting the time/mileage calculator.)

You're probably right that the granularity of the measurements that Infiniti uses for distance and fuel volume are just not fine enough to give tenth-by-tenth precision on the mileage in just a couple hundred miles. It just struck me as strange initially that the display increments always tracked up and down through the same sequence.

For what its worth, getting nearly 21mpg in my type of city driving is about 15% better than I was getting with my last BMW. If that translates similarly to highway driving, then I might expect 27 to 28 mpg on the highway.