[NOS2Go4Me]

It's probably half injector timing and half vacuum reading. My Escape has the digital equivalent to that but it reads in "amounts" of fuel as represented by a declining bar graph, not numbers.

Is there a resettable average fuel economy gauge as well? Reset it when you're getting that reading and cruise for 5-10 minutes at that speed if possible. That will give you a much better idea if it's real or if it's just a vacuum gauge. I did that with mine and averaged 9L/100KMs.

I know you're averaging 30MPG but that "instant" average reading would tell you whether the gauge is just fluff or not.

Pic of the fuel economy meter: