Hang Time: Exploiting ECU Fuel Maps for Fuel Efficiency

[dj92]

I think this trick is based on the acceleration enrichment.
It's used to let the engine pull stronger when you want to accelerate, and by releasing the pedal a bit, the ECU stops this enrichment which results in a better MPG.
It did not really work for me, shifting to the 5th gear from 18MPH on improved my in-town MPG this morning from 47 to 49.
However, my record on a level road outside the city was 58 :)