Y2K1S2K - You're suffering from insufficient data.

You'll need to run through several tanks of gas before you can have an accurate idea of mileage. I do mileage calculations as an excercise in an environmental studies class, and the biggest problem I see in these calculations is poor record keeping. The method you described is inaccurate because of the assumptions you made. As was mentioned, much less than 6.6 gallons has been used when your guage reads 1/2 full.

Here's the proceedure to follow:
1. Fill up your gasoline tank and reset the trip meter.
2. Drive until the tank reads 1/4 or less.
3. Refill the tank.
4. Divide miles driven by gasoline consumed and voila! MPG.

Step 2 is important, because it averages your mileage over a longer period of time. In fact, you won't really know what your mileage is for several fill-ups. Variables such as the angle of your car when filling up, the sensitivity of the gas pump shut off detector, ambient temperature, etc., all play a role in producing error. I've been tracking gasoline usage in my vehicles for several years, and there is quite a bit of variance from tank to tank, even if I'm doing the same type of driving. I'm averaging 25.0 mpg in the S2000. My previous Honda, an '89 Si hatchback averaged 31.8 mpg, and my wife averages 16.0 mpg in her F-150, so it could be better or worse.

Report back to us with your updated numbers. I bet you will be pleasantly surprised.

 

Typically, with moderate VTEC usage, I get about 240 miles per tank (with about 2 energy bars remaining on the fuel gauge). On a long trip, no VTEC, fill up and drive on the interstate, I get about 300 miles per tank with 2 bars left.

 

My fisrt few tanks I was getting 200 km, after it broke itself in I'm up to about 360 km per tank. Don't worry it will pick up