Sorry, I didn't get a chance to finish my previous post...
During the first hundreds miles, I got 21-22 MPG. Recently, at around 3,500 miles, I got 44.5 MPG on a roundtrip DC-NYC (that's I-95 and the NJ Turnpike).
Today, at 4,000, I get about 35 CITY!
So, it gets better.
As for the Scangauge, I hope that somewhere in those thread you can find the perfect setting.
Don't get discouraged... and have many smiling miles!