FILLD - Tap a button and get a tank of gas delivered to your car
Plot Digitizer - All-in-One Tool to Extract Data from Graphs, Plots & Images
Fuelio - Track your fill-ups, fuel consumption, fuel costs and save money.
Engauge Digitizer - This open source, digitizing software converts an image file showing a graph or map, into numbers.
Mileage - A Mileage tracker for an Android-based phone.
DataThief III - DataThief III is a program to extract (reverse engineer) data points from a graph.