Why doesn't the gas warning light come on when you have a gallon left, instead it comes on with 1/3 gal. left

Question

I get about 20 miles per gallon but when the gas warning light comes on I get about 7 miles before it runs out.

Answer 1

Depends on the manufacturer. On one of my Dakotas, the light comes on with 7 gallons left in my 22 gallon tank, on my other Dakota, which is newer and is the R/T version, it comes on with 4 gallons left. The whole drop in gas mileage is depending on the sensor in your gas tank, On my trucks, the 1st half tank of gas goes by kinda slow, but after the 1/2 tank mark, it drops quicker. You're still getting the same gas mileage, just the way the sensor reads you gas level is what makes it seem like you are getting crappier gas mileage.

Answer 2

Your gas mileage is greatly reduced as you have less gas in the tank. You get the best gas mileage when your tank is full. That is when it runs at peak performance. The more often you run your car until the gas light comes on, the less efficient your engine, and the more damage you do to your catalytic converter. Always fill up at half-a-tank.

Answer 3

mine comes on when i have 2 gal left