Quote:
Originally Posted by jeepmor
Data is from the car itself via gauges. I do record fill ups via paper log, but didn't check. Just Looking at the car gauge.
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Unfortunately you can't trust that thing. It is estimating your mileage by average fuel flow rather than actual miles driven divided by actual fuel used. I installed a mileage calculator on my phone (which does the pencil and paper calculation for you at each fill up), and the car's computer is consistently 3 to 4 mpg off.
If you use the car's computer, that bump after highway use could just be a side effect of the way the car calculates fuel economy. If it's averaging fuel flow, and you just had a long period of lower fuel flow, it's going to average that into the initial calculation back in city driving. It would appear to have a bump whether there really is one or not.
Do it with real numbers instead. There's no reason to have to keep a notebook and do math when you can download an app for your phone that will do it all for you.