On Top Of E Line Vs. On Bottom Of E Line
On top of E line you can squeeze almost 20-30 miles before it gets below the E line. You're in trouble if you level your head with the gauge dead center and the needle is completely below the "E-" tick. At this point you have about 14-18 miles of hypermile driving left before it'll start to smell like burnt cinnamon rolls (usually not a good sign for any car.)
Hypermileing refers to driving only with slow gradual speed changes, no sudden brakes and no sudden pedal to the floor starts. Just barely enough to keep the car going and keeping up with the slowest of traffic. You can get quite a bit more distance this way. QUITE a bit.
Provided of course that your gauge is still in proper working order.