When you are at "E" there is still roughly 5-8 gallons of gas in there.

 

Just an FYI but the large tank is 36 gallons and has 8 gallons left when the low fuel light turns on.

 

My 35 gal tank gives me the low gas light and I fill up with usually 22 gallons. I was in the middle of nowhere on an Indian reservation once, and it was getting sketchy. Everytime I'd go up a hill, the gauge would float up to a quarter tank, and then down the hill it would touch empty. As it turned out, the extra 12 gallons really came in handy.

 

My gauge lies..... Once it gets below about half a tank (on the gauge.....) it floats in a major way. On acceleration, it goes down below a quarter.... when I stop, it comes back up. Personally, I think the gauge stays on full for most of the time, and the gauge reads the bottom half of the tank......

 

I have the opposite experience. My gauge goes up when I accelerate (or have a payload) and down when I slow down or point downhill.