Our mpg dropped from 45 to 34-36 after our first tank of E10. We bought the Civic Hbrd to help our budget (in the long run) and to do a little to help with not wasting natural resources. Is there a safe additive which isn’t costly to help us return to the advertised and experienced MPG?
That’s a far larger drop in fuel economy than can be explained by switch to E10. But don’t panic yet- one tank isn’t enough to accurately gauge your fuel economy. If the drop remains, something else is going on, though.
There is no additive to restore your previous fuel economy.
I’m not convinced that either of your figures is accurate. Give it more time. But to answer your question about additives, there is nothing on the market, nothing at all, to up your mpg. In general, put nothing in your fuel tank except gasoline.