Av MPG Readout vs Calculated

[Jim Allen]

I'm sure most of you have noted that if you check mpg the old fashioned way, the average MPG readings on the Gryphon will be significantly higher than the calculated MPG from miles driven/gallons used. The F-150 is pretty easy to fill consistently but even when the the two values are recoded over a year and averaged separately, I show an average of 14.7 mpg using a g/mile calc vs 16.6 mpg from recording the screen average at every fillup (and reset each time). That's about a 11+ percent difference. Yes, my tire circumference is measured to the millimeter and loaded into the custom settings. My speed and odometer have been checked against mile markers, radar units and GPS and are accurate.

Comments? Other observations?