I have had 3 cars so far in my driving life…a Buick, a Chevrolet, and a Toyota. In all 3 of them, I have noticed the same thing–The gas meter on the dashboard is not accurate. I’ll explain. My current car will get approx. 325-350 miles per full tank of gas. So, whenever I have driven 160-175 miles on a full tank, the gas meter should read pretty damn close to 1/2 full, right? But it never does. At 175 miles, it always reads about 3/5 full…In fact, when it actually DOES read 1/2 full, I have driven about 210-230 miles. My previous 2 cars have done the same thing. Anyone else notice this? Any thoughts as to why?
This is just a guess but:
The gas reading is based on a little floater inside your gas tank. The floater device essentially “reads” it position based on it’s height in the gas tank. Since the gas tank is irregularly shaped (curved at the bottom) there would have to be a kind of “scaling adjustment” done to display a true gas level. I suspect that car companies don’t bother to make this scaling adjustment, and typically it is probably pretty small but for some cars it probably is more considerable and they still don’t bother.
If the gas tank were perfectly square or round then the floater would yield a true reading.
What more could you expect from somebody who lets people kick him to the head?
It depends on the driving you do. If, for the first half of a tank you do a lot of highway driving, you will get better mileage and go further. If, for the 2nd half it’s a lot of stop and go in a city, you will get less mileage. Just because you have driven 200 miles on 1/2 a tank, does not mean you will always get 200 miles for 1/2 a tank. It depends on the type of driving involved. It may average out to 200 over time, but it most likely won’t when you look at it on an infrequent basis.
Well, shut my mouth. It’s also illegal to put squirrels down your pants for the purposes of gambling.
Mullinator – I know what you are saying, and you are correct in that I can’t assume to get the same mileage…highway vs. city, “leadfooting”, etc…but this is a constant thing I am noticing–it happens EVERY time, not on “an infrequent basis”. I guess that’s one way I am turning into my father…being overly anal about gas mileage. 
Isaw this in a book once. But it was phrased another way. The person asked why when it hit half full it would drop much more quickly than from full to half full. Is that what you are saying?
Handy,
Yes, that’s exactly what I am saying. I like Glitch’s explanation…what did that book say?