How accurate have you guys found it to be when comparing the average mpg vs hand calculated?

 

I calculate between 15-16 mpg when i stop at the pump while the overhead computer usualy reads 12.5-13. Other than the temp and direction I don't use the overhead comp for anything.I dont have a need for a four digit tripometer and I cant even figure out what the heck the timer like thing is for.

 

Change the size of your tires and, the things off.
I use it for "Just-About-What-I'm-Getting" source.
(By the way,.. I'm still looking for a replacement for my burn't up one).

 

When doing most city or mostly highway the computer is close to what i get. I believe that the computer calculated mpg is based on the preveise 100 miles or so. This is based on my dad and I doing some test experiments with a dakota, ram, and t &c minivan. And also it seems to be the same for his new charger.

 

umm i reset mine every time i get gas, almost weekly, and it usually comes out to within .1-.2 mpg of what i hand calc, (as long as i am the only driver) its actually pretty good as long as you drive consistantly, which surprised me

 

thanks for the info... on my CTD it is refered to as the lie-o-meter... off by +4~+5... rediculous. the OH on the Dak said 18's which was pretty good. the needle seemed to agree with it as it barely budged over 70 miles. I guess the real test will be when I fill it up & drive it long distance.

 

as you drive more at steady speeds they get more accurate, at least mine does