i jus noticed that on the avg mpg and tank mpg display seems to be stuck ...on the avg mpg display its stuck at 21.9 n the tank avg mpg is stuck at 19.7
it hasnt changed to any thing lower or higher.. my driving style isnt the same all the time i like to speed once in a while bt it seems to be stuck on this figures. is this somthing to be worried about?

 

Holding the disp button down on avg mpg will reset it. After being reset, it should be very easy to influence with your right foot. I've never reset mine, and with nearly 10,000 miles on the tank, it appears "stuck". However, over the course of a long trip (e.g. a few tankfuls on cruise control, it will bump up a tenth).

The tank average resets when you fill up. It is VERY easy to change early in the tank, and becomes more difficult (but still not hard) towards the end.

 

kool thanks it workd perfectly got scared for a bit, but the tank mpg still seems to only change a tenth from 19.7 to 19.6 ?

 

That is probably just because you have a lot of miles on this tank already. As Bichon said, the mathematical significance of instantaneous fuel economy decreases with each mile driven. It will change very fast when you first fill up, and very slowly when your tank is near empty.

 

It is similar to the difference a poor grade on a test effects your overall average at the beginning of the semester versus the end of the semester.