You can probably improve your gas mileage by 8 to 10% by monitoring average and real time current mpg. The game becomes trying to keep your real time mileage higher than your average. On the very first trip my right foot got quite and education and we improved 9% on a roundtrip we had made several times before.
I also run transmission fluid temp and coolant temp, nice to see the digital display, no guesswork. We are currently negotiating on a new C purchase and you better believe I will be taking the Scan Gauge out of my truck and putting it in the new rig. :C