Originally Posted By: Gokhan
When will people learn not to report gas-mileage observations without doing several controlled runs? It's a rhetorical question. No one has the means to do such controlled runs and no one should report gas mileage and make precise claims. Gas mileage depends wildly on many factors. You miss the green light -- that could subtract 1 MPG. You miss another one, you idle more, different temperature, etc., etc. On top of that, there are measurement errors. Reading the fuel gauge for mileage calculations is absurd. Even the fuel pump readings are unreliable because how much fuel you put depends on the incline and pump.
Next time you say 22 MPG, note that it means 17 - 27 MPG.
I'm a creature of habit and I live in small town, I may be closer to controlled runs than you think. Traffic is never a variable in fact I usually don't get out of work until 5:10 and by that time I've missed rush hour and there is only one stop sign and two lights in between work and home. If it so absurd why do I consistently see the same readings. Using my Buick as and example since I've owned it longer, when the light comes on the gas gauge my trip meter is usually between 190 and 210 miles, very rarely does it waiver. These are all city miles of course, it would be more if I made a highway run. With a 16 gallon tank that is only a little over 1 mpg difference. These are non winter readings in the winter you can drop that 20 or 30 or more miles since it idles more its not as consistent.
With my truck that 1/8 of a tank works out to four gallons. That means my truck used four gallons of gas less in 150 miles than usual, even it its off by a couple gallons its still a nice jump.
This was only an observation and wondered if any one else had noticed something similar, I wasn't looking to publish my observations.