introduction

http://www.thinkgeek.com/gadgets/car/ae12/

webpage

http://www.plxkiwi.net/product/mpg.php

the computer built into the meter
has programs to 'teach' you to be a driver who can get better MPG
when you desire to

this meter
plus the Scangauge-II
and the installation of a simple old vacuum gauge
are written up in Popular Mechanics magazine this month

 

The MPG meter goes back 30 years. Just a vacuum gauge with numbers on it. Quite effective. If my Dodges had instant economy as well as average economy on the overhead like Ford/Lincoln does, it would also make a great tool for better driving. I use my overhead avg econ. as a tool to keep my foot light to always try to keep the number as high as possible.

My average highway economy in my Hemi Ram was just under 20 before the Predator 93 octane tune. Now 22 is obtainable.
This is after a 120 mile trip @ 65mph backed up by a refill and doing the math.

 

buy a vacuum gauge and learn how to read it... lol a ton cheaper then that thing... and does the exact same thing