[SentraSE-R]

The graphs lie. You didn't average 62 mpg on the first graph. You tried to take the average of the ~90 mpg X 60 seconds and 15 mpg X 45 seconds, but it isn't done that way.

There's a lot of rounding error, but here's why I think your Mustang only got 27 mpg on that first graph, not 62 mpg. it's backed by my real world P&G observations, where I typically see 250-300 mpg on glides from 60-45 mph, and 15-20 mpg on pulses of half the glide duration, while averaging a real world 45-50 mpg.

You've got ~45 seconds of pulse time in graph 1. Assuming you average 55 mph pulsing from 45-60 mph, you've traveled .6875 miles during pulsing. Assuming you average 15 mpg during those pulses, you consume .04583 gal during pulsing.

You've got ~60 seconds of glide time in graph 1. Assuming the same 55 mph average during gliding, you travel .9167 miles during gliding. Assuming you average 90 mpg during gliding, you consume .01019 gal. during gliding.

Total distance traveled = 1.5042 miles. Total fuel consumed = .05602 gal. 1.5042 mi/.05602 gal = 26.85 mpg.