I've had this happen several times. I refuel and that tank gets significantly lower fuel mileage than the tank before or the one after. I have had this happen on long trips where the conditions didn't change significantly, and I am reasonably sure the fuel was different.
I know seasonal fuel formulations are a possible factor, but I have had it happen before seasonal formulations, and during times when I doubt the formulations changed.
I think it happens with a out of spec alcohol mix, over 10%, since alcohol blends have a reputation of decreasing mileage.
I have also had the situation where I picked up a tank of gas that gave better than normal mileage. I assume it was all gasoline.
What else could change in fuel to give a 3-4 mpg loss with a fuel purchase?
The mileage computer in my car is pretty reliable and I can tell when I get some bad gas real quick.
I know seasonal fuel formulations are a possible factor, but I have had it happen before seasonal formulations, and during times when I doubt the formulations changed.
I think it happens with a out of spec alcohol mix, over 10%, since alcohol blends have a reputation of decreasing mileage.
I have also had the situation where I picked up a tank of gas that gave better than normal mileage. I assume it was all gasoline.
What else could change in fuel to give a 3-4 mpg loss with a fuel purchase?
The mileage computer in my car is pretty reliable and I can tell when I get some bad gas real quick.
