Originally Posted by lymphomaniac
My gut feeling says ethanol content is to blame.
I doubt ethanol is fully to blame. Sure it has less energy and all, but we have to burn it 100% of the time here in MN. 10% mix all year. Yet when the winter blend gas comes (still with 10% ethanol), mpg takes a good hit of about 3 to 4 mpg. There are so many additives in today's gasoline who knows whats the real cause.
I was gettting 35 to sometimes 37mpg this past summer. Now since mid October its dropped to 32ish. Ethanol content didn't change.
Did I read your calculations right??? Rour gauge says 30mpg and you calculated 23?? thats way off. Most of us are off by 1 to 3 mpg.