How do YOU calculate your M.P.G.?

[FlipTrac_511]

I agree, distance driven divided by gas consumed in that distance, which pretty much translates to miles divided by gallons of gas.



I've had my Trac for over two years now and I still calculate mileage at each fill-up by how many miles I drove since the last fill-up, divided by how many gallons I just put in (I always pump to full).



You're calculating right tracnblack, and you're getting great mileage. My best was about 20mpg on a road trip, but I used to average around 17mpg routine driving. I haven't been driving on the freeways lately and it's dropped to around 14mpg. I do have new tires and been using prem. octane perf. tune.

 

[Richard L]

tracnblack,

That is the correct way to calculate mileage, however that is only one tank of gas and does not represent a true average (except for that one tank). There issome room for error because of your rounding. You rounded your mileage at the full mile rather than the 10th's of a mile, and you rounded the gallons of gas to the tenth when most.



Also, you stoped pumping at exactly $52, which may not have really filled the tank as full as the previous fill up. It's fairly easy to exceed the capacity of the Sport Trac's gas tank by 2-3 gallons. When I want to get an accurate MPG I fill the tank until the gas is at the filler-pipe restrictor plate. Then I drive as far as I want, and refill the tank back up to the restrictor plate again. That's the only way to know the exact amount of gas used. It also is more accurate if you fill-up both times at the same pump so there will be no variations.



I have driven over 440 miles on a tank of gas in my 2003 Sport Trac and got 21.3 MPG for that tank averaging about 75 MPH. I have also exceeded 22.5 MPG for a tank of gas, but that's a just single tank under ideal conditions.



In real world driving your mileage can easily very 2 or more MPG just due to traffic, catching one extra light, or having to wait at a stop light a few seconds longer than usual. Then there's weather, temperature, tire pressures, and other nearly insignificant variations from day to day even when driving back and forth to work the exact same way every day.



I personally believe that you need to drive at least 1000 miles or 3 tanks of gas in your daily driving to even consider that an average MPG. If you connedcted an accurate instantanious MPG computer to your Sport Trac you would probably see momentary readings of 30 MPG or more as well as 0 MPG when stopped at a traffic light.



Some people make all the rounding errors, and short fill their tank and then swear they get 27 MPG.



...Rich

 

[Mike Wilson]

RichardL,... It seems that you do it exactly the same way as I do, and you have "caught"

my little indiscretions, such as rounding up or down, but I swear, never any more than

.50 cents at a time (ex. said I put in $52.00, when it was actually $52.30), and never

more than 1 mile at a time, (ex. said I had 425 mi., when it was actually 424.1 mi.).

Just got this exact info off of the receipt that I had filled up on the other day!

I'm not into the rounding errors, that much that I am going to try to fool myself into

thinking that I am gettin' 27 m.p.g.! If some of you might read, or have read some of my

previous posts, almost since I got the 'trac in 7/05, and started to read about the bad

m.p.g. figures some of you were having, I have tried to post accurate results with figures

since then. As you posted, R'L., this (should be) close to a one year (average) for me, give

or take a m.p.g., over the one year, 21,250 mile life of the trac, so far!, I still come up

with an overall average of 20.9 miles per gallon, on somewhat hilly terrain, for 50% of

my daily, 82 mile round trip commute! And by the way of all the variables,you mentioned,

you forgot the Winter/Summer Fuel Blend difference! I've hear that can be a factor in some

areas of the country, as well.

 

[Richard L]

tracnblack,

My point was that calculating average MPG for a single tank of gas is highly inaccurate unless you minimize all rounding errors. These are small details that can cause inaccurate MPG readings in either direction...Too hight or too low. Over a period of several tanks full, these small rounding errors tend to even out and are not significant.



I believe that many of the extremely high and low MPG readings posted here are misleading since they are usually a single tank reading where rounding or cutting off the pump or short-filling the tank.



If you want to measure how much gas you used in a single tank full, you must fill there gas tank to the exact same level before and after the drive. The only way to know exactly how full the tank is would be to see the exact level. That's why I recommend that you fill the tank all the way up to the restrictor plate in the filler neck. You can't just rely on when the pump shuts off because different pumps have different shut-off sensetivity.



...Rich

 

[Mike Wilson]

RichardL,

Again, I agree! That, again, is the way I do it. I could be no more off than 1 mile per

gallon, regardless of the rounding errors, on either side of the calculation ( $ -vs- gallons).

I try to be honest and accurate, not just for myself, but for all of the other members!

 

[R 2]

Interested to see how the 07 ST Limited owners use their instantaneous MPG tool on their message center for gaging MPG?

 

[kil roy]

go to this page and download Vehicle Record System 4.1F.1



http://www.download.com/3120-20_4-0-1-0.html?qt=vehicle+record&author=&titlename=&desc=&dlcount=&daysback=&swlink=&gfiletype=&os=&li=49&dlsize=&ca=





it is free for 3 vehicles and tracks everything from payments, insurance,

maintenance, fuel mileage and usage. pretty much everything that has

to do with motorized vehicles.

i have been using it for about 5 years and love it.

 

[Jake Levin]

I do it the same way as judd, and do the same thing as Jeff, I reset the tripometer at each fill up, use the same pump at the same gas station unless I don't have enough gas to get back there. I write down my mileage to the tenth on my receipt and then input the gallons (to the thousandth) and miles in our own handy dandy log on Myst. My mpgs bounced around alot from fillup to fillup until I started using only 1 gas station repeatedly. Since then my mpgs are pretty consistent (check my log) and I can see overall what my average is. Still not getting in the 20s though