There are 3 modes in computer for calculating mileage. Instant, since start and since refuel. All should be quoting numbers from "since refuel" and even then those can be skewed if you just filled up and had a good stretch in the City. Try looking at that mode on an empty tank before fill up and still tell me you get 30+ mpg in a city while driving spiritedly. I don't believe it, because I've tried it.
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Aargh...the gas mileage thread. There are different urban driving conditions and different driving habits. Just because you can't get 30mpg doesn't mean those who do are lying.
today i checked the computer, 205 miles since fillup, all urban driving, 28.8 mph average with 30.2 mpg average over those 205 miles...ALL urban.
Keep in mind my urban situation, i have a urban commute that involves 6 miles of "beltline" of 55 MPH. ALso another frequent stretch is 5 miles of 40 MPH with just a few stop lites. It all depends upon the actual urban routes and number of stops etc, but my weekly urban average is almost always over 30 mpg. Now as far as highway, no i don't think i've every averaged 40 but 36-38 seems about normal. Spirited rural driving, that's a whole nuther story.