[WINGNUT200]

I switched from 92 octane to 91 octane with stp fuel additive at the local gas station. I noticed my mileage went from 86mpg to 79mpg. The weather has been really strange going from 90 down to the 70's. I wonder if the 1 point difference is worth 7mpg?

 

[qwerty]

I switched from 92 octane to 91 octane with stp fuel additive at the local gas station. I noticed my mileage went from 86mpg to 79mpg. The weather has been really strange going from 90 down to the 70's. I wonder if the 1 point difference is worth 7mpg?

Sounds like more ethanol in the lower octane choice.