maybe i'm analyzing this too much.

filled up @1/4 tank - mpg = 18.5
@1/20 tank(almost empty) - mpg = 16
@1/2 tank - mpg = 14

i'll try the 1/4 tank again and report back.

anyone else this crazy about gas?!

 

Gas is heavy.

 

yes. gas is heavy. you will get better gas mileage with the last gallon in your tank than the first

 

Then why did it get worse when it was almost empty, compared to better at a 1/4 tank.

gas is heavy, but i belive the variances your seeing may just be from differnt driving habits, even if you dont realize it, sometime's you drive different.

that, or its possesed.

wade

 

also, you may not be filling it up the same each time. different pumps may have different shot of things (can't think of the word)

 

No, I have herd of this. A guy once told me that you always get better milage the first half tank than the secnond. I have found this to be true myself so I have made a habit of keeping it full. Anyone know why?

 

how are you mesuring your gas milelage? the gas gauge is not an accurate tool to gauge mileage.

 

yah exactly, according to my gauge, i always get significantly more miles on the first half of the tank and then when the gauge is below halfway it goes soo fast, so i've learned not to base it on anything other than miles i got per how many gallons i had to fill up. i've never tested the actual mileage of the 1st and 2nd half of the tank though.

 

Exactly - simple logic says that if my gas gauge is correct & I can drive 100 mile between the gauge reading Full and 3/4, then I should be able to drive 100 miles between the guage reading 1/2 and 1/4. Somehow I only get about 20 miles between 1/2 and 1/4. Somehow, I can get 75 miles out of the last 1/8 of a tank, though.

 

the only way to figure your milage is to fill all the way up and record the gallons you put in...then drive x amount of miles...and fill up to the top agian. devide gallons used by miles driven. theres your milage.

 

This is what I do and I still maintain that I get better milage on the first 8 gallons compaired to the second.

 

I have been keeping gas MPG logs every fillup since day one of owning the 4Runner from November of '98.

I see this same exact thing too.
Better mileage during the first half, even when the rig is heavier from more gas.

 

i beleive it is also true of this theory better gas the first half of the tank, i have no actuall proof of this however i fill up on average once a week, i dont do anything out of the ordinary everyday, but it seems the first half of the tnak lasts for 5 days, then all of the sudden the last half lasts for 2...... and i mena 7 day week solid, i dotn have actual weekend days where i do more driving or anything, its pretty much the same.....

 

the gas gauge is inaccurate so i use the amt that it takes to fill up from the gas station and the mileage for each tank.

 

If you are only looking at the gas gauge remember the all the gas in the fill tube. I can go 100 miles in my corolla before the needle is below full on the gauge.

 

listen guys,the gauge is not a way you can judge upon. check the size of your tank,now when your "empty" record how much gas you put in. i bet its a couple gallons less then the tank can hold.
yeah,on my truck and even my v8 mustang,the needle stays at full for 70 miles or so. is it still full? no!!

 

Not sure about better gas mileage on first half vs. second half, but the more gas it takes to fill your tank, the lower your margin of error will be. As an example, if you go 20 miles, then fill your tank it may take 1 -1.5 gal (0.5 gal difference) to fill, the variation due to different pumps, how fast the pump is filling, is there an air bubble etc., but if you go 200 miles and it take 10-10.5gal (0.5 gal difference) to fill, variations due to same reasons, the 200 mile tank will yield a better calculation with less, inherent, "margin of error".

 

I agree with the posts above. I definitely get the best gas mileage in the first quarter tank and the last quarter tank.. but don't forget, the gas gauge isn't linear.

 

so your admittendly conterdicting yourself boggy...correct?

my point is this. your not really getting better mileage just because it takes longer for your gauge to catch up.

 

that doesn't mean a thing.. i have noticed that i DO get better mileage the first quarter of a tank (measured by how many gallons i fill / miles i drove).. I just mentioned the guage wasn't linear to explain anomalies in the rate at which the guage drops. 2 completely different statements. In all actuality, the guage was designed to be linear, so it may be more accurate on some toyotas than others.