Strange MPG findings during road trip to FL

[66sprint6]

Took advantage of the long weekend and hit up Pensacola Florida with my girlfriend. Put new tires, struts and brakes on the Escort and hit the road. The AC doesnt work so we ran with the windows down the entire way there and averaged 65-70mph the entire trip. No traffic, only stopped once to eat and filled up the minute we got off the interstate in FL. I was actually a little bummed when the calculations came up to 41mpg. I get that around town on good tanks so I figured Ide be alot higher on the interstate. Bummed out I hit the road to the hotel, beach and all over the islands. On the way out of Pensacola heading home I filled up at the same gas station and was SHOCKED by what I saw. I had logged 87 miles of driving over the weekend and only used 1.4 gallons of gas That comes out to 62mpg which made me extremely skeptical. I did the math a couple more times, even had my girlfriend check it and it all adds up. Ive even looked at where we went and how many miles it all was and it all adds up mathmatically...it just doesnt make sense. Hit the road for home and tried to stay around 65 mph instead of 70. Filled up once we got back and got 41 mpg again lol. I know speed factors into aerodynamics, as does running the windows down but I figured Ide see alot higher numbers on the interstate and have never dreamed of seeing such high numbers on short, around town trips. Figured Ide share my weekend of findings with you guys!
Matt

[mcrews]

Running the A?C arojund town on a small engine probaly is a larger drain than when on a freeway.
Also, my ( unoficial) test on windows down at dreeway speeds is a 20% lose.

So in actuallity, the rewults makes sense.

[tru]

inaccurate re-fills at 1.4 gallons will lead to skewed mileage numbers

[gone-ot]

...small fillups (<1/4 tank) almost always yield skewed results, which is why ScanGauge (and others) recommend almost FULL-tank (>3/4 tank) fillups when attempting to "calibrate" their SGII.

[66sprint6]

The AC doesnt work so it was windows down at all times or die of heat LOL. I figured the small fillup would be skewed somehow, and I realize that my method of measuring MPG can be skewed by so many different variables so a MPGuino is probably in my near future. 20% loss at freeway speeds huh, thats HUGE!!! If the weather woulda been nice enough to allow windows up driving I woulda been happy to do so but we woulda died lol. May have to wait till Fall to get any good highways numbers.
Matt

[user removed]

Just put the fill ups together for your average. Your fuel log will average them out anyway.

regards
Mech

[66sprint6]

Yeah I put them all in individually for each and every fill up. Are you sayin to add up all the miles and gallons used on the trip and put them as one entry?
Matt

[Soichiro]

Originally Posted by Old Tele man

...small fillups (<1/4 tank) almost always yield skewed results, which is why ScanGauge (and others) recommend almost FULL-tank (>3/4 tank) fillups when attempting to "calibrate" their SGII.

It's better to wait until the tank is low to fillup anyway. Less gas in the tank = lighter car = better MPG.

[66sprint6]

Yeah, I only filled back up so that I wouldnt have to do so along the way home. The trip back is about 444 miles and I was able to make it on one tank. I NEVER fill up unless the tank is empty otherwise!
Matt

[Fat Charlie]

Originally Posted by 66sprint6

Yeah I put them all in individually for each and every fill up. Are you sayin to add up all the miles and gallons used on the trip and put them as one entry?
Matt

Enter them all in as different fill ups. Your overall average isn't going to change. You'll just have that one green line sticking way up is all.