My '96 has a 20 gallon tank................
I have run it pretty far under the "E" mark a few different times.
and the most I ever put in was around 18 gallons..........I have never ran it completely dry.
When the light comes on steady, it takes around 15 gallons to fill it full.

 

Righteous , thanks for info .... wasnt sure if it went passed the E mark

 

My '01 has a 20 gallon tank. I would never know it by the way the fuel gauge works. The fuel gauge is marked off in eighths. The low fuel warning light comes on when the needle hits the last eighth of a tank. And once the needle hits the last marker, you can see the needle move as you drive along. It's like your getting 5 mpg all of a sudden. I've taken the needle below the "E" but never needed 18 gallons to fill it up.