I just confused the service manager at my dealership with my question, so I decided to ask it here, knowing there is a lot of wisdom and experience in this forum.
It is such a minor thing, but I am a few days from being out of my extended warranty, and my overhead computer seems increasingly inaccurate when measuring my fuel economy. When new and for the first couple years it was pretty accurate compared to had calculation.
Beginning about two years ago, it started consistently overestimating my actual mileage and becoming worse with time.
Now I am consistently 20% off or about 3.5-4.0 mpg off when compared to hand calculating.
Has this been an issue for others? Can it be recalibrated? If it is broke, I would like to use my warranty to fix it.

Any help, as always is very much appreciated.

 

its a known issue and no fix really. nick named the overhead lieometer. best to stick with hand calculating

 

Have you had any flashes performed when in for service? Mine started out about 1-1.5mpg high, since the last flash it reads 20-22mpg when I'm getting 16-17mpg hand-calc. I've seen as high as 24mpg on the O/H during long trips.

P.S. I find the DTE to be much more of an accurate reading.

 

My '02 has always lied by 4 to 5 mpg's. Really sorry computer.

 

Yeah, not much you can do. I call it the overhead liar.

 

The only real thing they are good for is bragging rights to people that don't know any better!

From the factory mine was off by about 3-4mpg but after getting the Smarty Jr. it is actually much closer now. Only off by about 1-2mpg.

 

Mine currently registers 28.5! (21 hand calc.)

 

Just leave it set to Temp and Heading. Only thing the 'Guess-O-Meter' is good for.

MikeyB

 

Yup. That is what mine stays on! Every now and then I check the MPG just to see what it thinks I'm getting

 

Mine is also consistently 4 to 5 mpg high, based on my normal daily driving routine. Knowing that, if it should suddenly take a significant drop this could be an indication of a problem elsewhere. But of course, a quick hand calculation to verify would be in order as well.

At least, thats my logic, is it flawed?

 

The lie-o-meter in both my trucks is the same way. Sometimes it will read as high as 27 MPG, which I know is a pipe dream, and other times its as low as 7 MPG.

Stick with hand calculations, and switch the gauge over to something more useful, like the direction and tempurature.




-Kris