I guess you can run down the trip button options and find the one that says how much fuel miles is left and work out the difference between the last time you checked it. But it's only an estimate, and you probably still have over a gallon of fuel left. That's all I can think of using (have used myself).
If you have miles and miles/gallon (which you can get from one of the eco monitor screens), you can just divide one by the other to get gallons used.
if you went 100 miles at 50 mpg, that would be 2 gallons. why can't they simply have a readout for that?
