jdoolitt

17 mpg X 17 gal = 289 miles
23 mpg x 17 gal = 391 miles

100 miles difference at fill-up ~ 5.8 gallons at 17 mpg
5.8 gal @ $3.00 = $17.4 <-- per fill-up.. what the granny driver is saving ( not 2-3 bucks).

TorontoIS

I had my IS350 delivered with snow tires on it and had been disappointed with the gas mileage. Last week I had the summers put on it and low and behold it is using one liter less per 100 kms already in city driving. It will be interesting to see how much better the summer tires are going to be than the winters as I get more kilometers on my IS.

fantom

Your posts are useless unless you indicate what engine you have, as in:

My 350 is averaging about 25 MPG on the highway and about 17.5 MPG in city driving.