The milage summary histograms for car models are a great feature; however, they can be rather misleading to glance at because the X axis isn't linear because milage values for which there are no data points are omitted. It seems it would make more sense to include bars (or spaces for bars) for every milage value between the minimum and maximum, perhaps excepting any extreme outliers.
Have you tried clicking the option located under the chart: "Show fuel-ups by: fuel-up number"? That will space them out evenly instead of by time.
I'm not sure what you mean by including bars or spaces for certain mileage values. Can you mock up an example of what you mean? That might help me understand what you're after. Maybe you could use a Fuelly export to build the chart you want in Excel?
I guess I wasn't clear on the page--I'm talking specifically about the histograms at the top of the pages summarizing everybody's results for a given car model, such as http://www.fuelly.com/car/honda/fit/2012 which (at present) lacks bars for 21-25 mpg and for 38 mpg since none of the averages fall at these values. I think it would be more consistent to have gaps or bars of zero height rather than skipping the averages and making the horizontal axis non-linear.
Ah, I see. I completely misunderstood which graphs you were talking about.
The issue with those charts at the top of model pages is space. If we include every point between the top and bottom numbers, the bars would end up being thin lines instead of bars. I think that would make it much harder to read the values.