Strange MPG spike

[LVI56]

I got a weird MPG spike. I average 24 MPG, but after a fuel up last week I got a spike up to 28, now it's back to 24. I just can't figure it out... all my odometer and fuel up data is correct, but the calculation is way off. I even tried adjusting some of the numbers a bit hoping maybe it would re-calculate, but it still stays up around 28.

Her's my log http://www.fuelly.com/driver/lvi56/mustang/log

[pb]

According to the numbers you went 318 miles on 11.19 gallons of gas. 318 divided by 11.19 is 28.4. Why do you feel like the calculation is way off?

[MMUK]

Perhaps the fuel pump clicked off earlier than usual (if the fuel foams up it will cause this to happen).

[Rubberdude88]

Ya... as MMUK said, you may have not gotten it quite full.

[LVI56]

Ah, early click off makes sense. Thanks guys!

[Charon]

That sort of error usually corrects itself on the next fuelup, when the mpg looks unusually low. That's also the reason you should use several fuel fills instead of only one to get a truer fuel consumption.