I recently switched to Chevron when I noticed that they were price competitive with Quik Trip.
I've been using QT and Shell exclusively, but when another Top Tier gasoline becomes price competitive, I figured I would give them a shot.
My gas mileage went down from a 23.X average to 20mpg. Figured it was just the change in the weather, pumping from a different pump, etc... But several tankfulls and it was still down at 20mpg.
Switched back to QT and it went immediately back up to 22mpg average. I figure another tank and I should have most of the Chevron fuel out and we'll see if I'm back up to my previous average.
I don't know why. Maybe more ethanol in the Chevron?
It didn't run poorly. Felt absolutely the same. Just didn't do as well on gas mileage.
Back in the MMT days, Chevron gas would stain my carbs floats, float bowls, and plugs redder than any other gasoline. But my bike always ran well on it.