I have experience a 20% drop in gasoline mileage when using fuel with Ethanol. Is this normal? It would appear the benefits of Ethanol are more than offset by the poor mileage it offers whereby you burn 20% more fuel to travel the same distance. (mileage going from 40 mpg to only 32 mpg when using fuel with Ethanol in a 2002 Saturn SL1) Are my observations confirm or disputed by others?
Is this for E10 or E85? E10 has caused 3-10% drop, E85 30+% drop. So 20% would be high for E10.
You might try a few more tanks of gas, unless you’ve had a few already. I agree that you could expect up to 10% drop with E10.
We get about 4% less mileage with 10% ethanol with a mix of urban and suburban driving over many tank fills using a fuel mileage computer in our car. Checking fuel mileage with one fill can make errors. The fill can vary depending on the levelness of the parking pad at a gas station, speed of fill if you stop at the first shutoff, season, driving habits, traffic density and more variables.
I agree that you could expect up to 10% drop with E10.
Are you sure that is what you intended to write? That would mean that the ethanol was not making any contribution at all.
If you are indeed seeing a 20% drop in fuel economy. Then it would indicate something else is at play here. E10 alone will not drop your mileage by that much.