gas gauge
 

Do any of you guys notice the second half of the tank seems to go quicker? I would think it would last longer cause theres less weight.

It really depends on the gauge and the technology it uses, a float would be inaccurate at full because it'll take in some fuel, and my Sonata's resistance based fuel gauge is inaccurate with 10% Ethanol based fuel (it fluctuates up and down whilst driving).

And then the car's still got 15L at least in the bottom of the tank when it's at "E" - so the paper that the gauge is printed on is deliberately inaccurate (to protect the pump of course).

When you fill up, does the needle go above F?

Do you stop for gas before the needle reaches E?

Then yes, you will travel more miles from fillup to halfway than from halfway to the next fillup :)

It depends if the lower half of the tank holds the same amount of fuel as the upper half!

Yup. My 98 Civic is the same. I've been driving this car every day for ten years. I have come to understand the gauge distortion this way: the low-fuel light comes on at 9.5-10.0 gallons burned, though the tank is 11.9. I have run it close to 11 gallons burned, all the while looking at the needle below "E" and the fuel light on and pumping problems developing (I don't recommend this experiment). So the needle will be on "E" when there are still about 2 gallons in the tank, while it will show over "F" without filling past the first click of the station pump.

...in 'words-of-one-syllable' the gas-gauge is not linear.

Yeah I have never filled even 11 gallons, most fillups are 9.5-10. How many miles would you recomend going with the gas light on?

As few miles as possible/convenient. You get more pumping losses to your FE when you work the pump harder at the bottom of the tank. And you'll wear out the pump faster. Maybe 10 - 20 miles past light on is a pretty good index. It comes on first on steep incline hills... that does not count to me. I look for it to be coming on in more common settings, like very mild hills. Hope that helps.