1st rule, never trust your gauge to tell you how much fuel you have (or have left). That is just an estimate bases on a reading in the tank, translated through a sensor and passed to your car's computer that is then translated back to the gauge. Many places to be incorrect or somewhat "off". Try checking the accuracy by filling the tank, driving until you have used 1/4 to 1/2 according to the gauge, then fill the tank again and see how much fuel you actually have used. Remember that a gauge reading E will not be bone dry. There is actually a gallon or two left so you don't panic and look for a station to fill up!
