Just found 93 octane (E-10) around me and decided to try a tank. Was using 91 ethanol free before. My MPG jumped from 11 to 13 instantly. Haven’t seen above 11.5 for the 5k I’ve had it. Drove around town for 10 miles stop-n-go and it’s holding at 13+/-. Does this sound like there’s a 93 tune on it that I wasn’t aware of (bought used)? How can I tell if there has been a tune out on without going to a dealer or buying a forscan device?