Well, I forgot to go to Autozone. Instead, I cleared the code myself by disconnecting the negative terminal of the battery.
Driving to work today on the 36% ethanol tank, I got over the East Chicago bridge without incident. I'm hopeful that this ethanol content won't throw a code.
Just looking at the mileage indicator on the dash, 36% ethanol gets a lot better mileage than 43% did.