<VV> GPS to measure MPG

[TiM M]

     When I bought my Rampside the odometer didn't work and it still doesn't. I installed a GPS in it to keep track of my miles driven. Being battery powered I have another meter that shows the instantaneous current draw. This is pretty much lime the old economy gauges that tell you how well you're doing. The harder you push on the pedal the higher the reading the more it's costing you. 
     I think it would be a great idea for the GPS folks to modify their software so you could put in your vehicles average MPG and the average per gallon cost. It could then calculate the cost of your trip and more importantly give you a readout in dollars and cents of what the trip is costing you. The manufacturers could add this option so you would be able to actually see the $$ difference in the way you drive. It would be a big help in the econo runs as well. I think the big three are still in denial. The latest add campaigns out here in CA are promoting how far their vehicles can go on a tank of gas. How do you improve this statistic? Bigger tanks...

TiM