All, I'm trying to calibrate a smartphone fuel consumption application on my vehicle, a 2009 Ford Fusion SE with the I-4 engine. I want to get a "control" varible to compare against the mileage readings I'm getting from Torque's Fuel Efficiency plugin. In order to do this, I want to have exactly one gallon of fuel in the tank, and see how many miles I can drive until it runs out of gas.
The problem is, it seems I cannot rely on the Fusion's message center to give me the real number. The message center's "Miles to E" feature says I have 0 miles left until empty, but I know that the car has fuel in reserve. According to the guy at CarQuest, Ford usually gives about 2 gallons worth of reserve fuel after you've hit "empty". Can anyone confirm this, or give me the actual amout that's held in reserve on the 2009 I-4 Fusion?