Astoundingly sudden high mileage yesterday

not sure what mean about mpg. i usually measure it by the tankful. i use the current reading for p&g etc., i never see that in one place. it goes from mid teens to 99.9 depending on what i'm doing. the average moves a bit on a new tank and less and less as i put more miles on it. what exactlyare you describing?

 

i also have an 08. i filled up yesterday and the average started in the upper 70's. then after 10 miles or so, it was in the low forties. by the time i got home, it was 53. it will probably hover in the low 50's for the tank, unless the weather changes drastically or i take some longer trips than my regular commute.

 

Hi howardbc, the one important thing that you didn't tell us was how many miles you had traveled since filling up when this happened.

I'm assuming that you reset MPG data when you filled up the tank (can you clarify this point). When you calculate the average MPG over just a few miles then of course you can get a lot of variation as a result (much like you do with the 5 minute averages).

For example I live on a hill so there are several destinations where I can travel around 10km and average only 2.5L/100k (94 MPG). So if I were to fill up here and then immediately drive one of these routes then my "average" MPG would be ridiculously high. Of course when I return it's more uphill so I only average 6.5L/100k (35 MPG) on the way home giving an overall average of about 4.5L/100k (52MPG) which is close to my true average MPG over a full tank.