display in the cluster, it shows that i get about 12 the city, and 17 or so hwy.. does that sound correct?

 

NO it sounds low probably should be around 18 city 23 hwy

 

thats waht i was thinking, what is a good way to check to see waht it may be? any input would be phenomenal

 

Divide the number of miles your car ran on a full tank by the number of gallons of gas your car holds.

 

yes I know that is the way to correctly find the numbers, but i was wondering why the dash one would be so far incorrect?

 

Oh sorry. Not sure why it's off, but if you watch it while you drive it changes with every input you make to the gas pedal and it averages that instead of taking the actual miles divided by tank capacity...could be the reason.

 

If I understood correctly, the on-board computer is using the past two seconds data, then average over the time from your last reset. So, if you leave the way it is and after few full tanks re-fill, the number should be fairly close to normal. If you reset it too often, the computer just don't have enough history to calculate the average.