Here are my results after 2,427 miles:
Low: 25.08 at 372 miles, lots of idling.
High: 41.70 at 1,423 miles, highway.
Average city: 28.90
Overall: 31.65.
Maximum fill up: 9.267 gallons. The fuel gage had indicated 0 gallons for at least 15 miles (frightening).
Also, please consider the following:
From The Wall Street Journal automotive reports:
(1) If your gas station uses a single pump for all grades and the previous customer used regular, you may receive as much as a half-gallon of regular fuel.
(2) If the EPA rating on your car was with with 100% gasoline and you are using the now-mandated 10% ethanol fuel, your mileage may be reduced by as much as 10%.
(3) EPA tests are run without air conditioning or lights.
These from my experience using a scan gage (and confirmed by other research sources):
(1) Use of headlights (DRLs, for example) reduces MPG by up to 3.5%.
(3) Use of air conditioning reduces MPG by approximately 10%.
From Road and Track:
You achieve maximum MPG by reaching cruising speed as quickly as possibly use the following technique: Use full throttle (maximum manifold air pressure and flow) and shift close to 2000 RPM. (High octane fuel would be mandatory.) Although you use more fuel for acceleration, the period involved is short and engine efficiency is high.