[UFO]

First thing I would do is verify or calibrate the vehicle fuel mileage reporting. Ensure your odometer is correctly measuring distance traveled, then log fuel consumed and compare to the mpg reported.

With my first tank I found my Chevy Colorado reported optimistically, vehicle computer reported 24.6, actual mileage 23.0, 6.8% high.

And definitely verify reported vs. actual when you are using different driving techniques. When I had not set up my Scangauge correctly on my previous vehicle, I was getting really high mileage numbers reported that were in fact worse than with my old driving technique. Fuel computers can be faked out.