Boring bike technical report

With my new air filter and plugs I though I would get a bump in gas mileage and some more peppiness. I was discouraged as this did not happen. However, it did happen when I filled up with regular octane gas. You see since Winnepeg, I have been putting 91 octane because I thought that it might burn better than regular. (my bike calls for regular and that is what I normally use) when I changed to regular as the station did not have 91 octane, the bike was transformed to it's old running style. I got 44 mpg and the pep was back. The next tank ran the same. However this third tank, I noticed some sluggishness and less mph. I did notice a little surging at times. However I have resolved not to worry so much about every little sound and mechanical happenings with the bike, I am way over sensitive. I need more faith, maybe this trip is giving me more faith...