Does the first half of your gas tank last longer than the second?

No vehicle's fuel guage can be very accurate, as the sensor that detects the fuel level could only be somewhat accurate when the car is sitting still and on perfectly level ground. Any other times, the fuel is sloshing around the tank and a real measurement would be impossible.

So, it is hard to tell at what point the fuel tank has used up exactly one tank of gas. Consider, too, the additional gallon or so of fuel in the fill pipe. Any level higher than the guage's sensor wouldn't register, and the guage's level wouldn't begin to drop until all that fuel was used up.

Any argument that the air in the tank, above the fuel making any difference in the pressure of the fuel in the system is bogus, since the engine's fuel pump, and injector systems put a fixed amount of gas in the cylindars, depending on demand. Also, any argument that the gas in the last half of the tank is more "contaminated" is also bogus, since the car's motion would tend to slosh the gasoline around and mix it up.

If ANY variance is fuel economy is true, assuming, otherwise, consistant driving habits, it is that warmer fuel contains less energy per volume than cold fuel. Warm gasoline expands in volume, but the energy contained remains constant. Gas station owners LOVE to have you buy fuel in warmer weather. The increased volume in their underground tanks means increased profits for them.

Nope. As you said, the more fuel, the more weight, it used to be when the tank got down a bit it evaporated more quickly, but that doesn't apply now with the sealed systems.

No fuel gage is totally accurate, and most of them move move slowly for the first half a tank, but the mileage is the same for the top of bottom half.

In some heavier cars having LESS gas in the tank gives it better mileage because the ECU (electronic control unit) restricts the flow of fuel from the injectors and doesn't let the driver punch the accelerator and use more fuel. But I think the first half of your tank is more mental than anything because unless you are in this kind of situation would you ever experience anything like using more gas at first or later.

Does milk go faster when you pour out the first half or the second half? It's always the same rate, however, the fuel gauge may be malfunctioning. I don't think the weight difference between a full tank and a half tank would be enough to worry with.

From personal experience I will say the first half of the tank seems to go slower than the second. However, I am not 100% sure it is not a psychological thing once the needle gets past the 1/2-way mark.

I have heard that too...

It appears that my second half goes faster than the first.

I do notice that when I have a full tank I can get to work two days on what reads a quarter of a tank ... and when I am down low it takes a quarter to get to work for one day (not two).

Yes, my gasoline gauge moves slower when I have more than 1/2 a tank, and faster when less than 1/2 a tank, not sure why, but I too can travel to work more times on a fuller tank than half a tank.

This has occurred in several cars that can recall.

This is in my opinion, all broken down to Boyle's Law.

P=1/V.

Kindly read up on that before commenting.

Thanks

That is how it seems sometimes but no i'm afraid not

No.........