[VegasDude]

Last fill-up was a bit of a short tank (for me) since I wanted to start my Summer FE challenge over at CleanMPG.com.

620.9 Mi
12.95 Gal
47.95 MPG

Why the sudden spike? I would assume it's because I drove 150 miles for ~55 MPG while doing some testing to determine my car's optimum speed and scouting out roads to perform a full tank run-thru. Also I've been getting even better at my daily commute and if you can believe it, still don't use A/C regularly. Again, the highway mileage isn't close to this.

I have gone back thru my tanks and added +2.5% to each distance. This is based on a GPS-Odometer discrepancy. During a typical drive the odometer with turn over 10.0 miles and the GPS will read 10.2 to 10.4 miles (based on of 8-11 satellites.) My correction factor may change with new tires or if I have a chance to use mile markers instead.

I've also noticed my analog speedo is about 3 mph slow depending on my speed, although the average speed returned by the computer is more accurate.

Edit- After checking the odometer again on perfectly straight roads at a constant speed there appears to be no problem, so I've removed any correction factor from my tanks. I believe the GPS wasn't so accurate at slower speeds in the city.