February 2006 MPG Averages

Sorry, the mileage was overall and not for the tank. The (short) tank miles were 249. MFD said 38.2 mpg. Now that the weather has warmed up and we're learning to drive more efficiently we've passed 42mpg on the current tank.

 

ah as i suspected. another reason why you should be resetting the MFD after every tank fillup. you were at 37.5 mpg @ 553 miles. if you have 42 mpg @800 miles you would be averaging over 55 mpg...see greater changes and real progress that way...make yourself feel good. measuring each tank on its own gives you goals and benchmarks to shoot for.

 

Er, that is with resetting the MFD trip odometer after each fillup. 42mpg is on current tank at about 7 bars now.

 

Got new tires and VentureTape finished today. On the way home I got gas. 241 on tank and 5.266 gal was all she would take. That comes to a calculated 45.8 mpg. But the MFD said 40.7 mpg for this trip (tank) setting. I was surprised by the 12% error. Is the MFD just an approximation? Or are tank refills inconsistent as far as topping off levels? Which is closer to true mpg?

 

For an individual tank, the calculated MPG and the MFD MPG can be way off. But they should stabilize over time. For example, my calculated lifetime MPG (total miles driven divided by total gallons filled) is 44.3, and my lifetime MFD MPG is 45.0, so they're within 2% of each other. Actually, my MFD doesn't display lifetime mileage, but I calculate how many gallons the MFD thinks I've consumed for each tank by dividing the miles for that tank by the MFD MPG for that tank. Then I add up all the gallon amounts and divide the total miles by that number.

Speaking of which, here's my fourth tank:


Tank miles: 415
Total miles: 1453
MFD mpg: 46.6
Gallons filled: 8.918
Price per gallon: $2.539
Calculated mpg: 46.5

Lifetime calculated mpg: 44.3