My pet peeve is that the octane level of regular, mid and premium varies from state to state. My owner’s manual says to use 86 octane gas. In Colorado where I live, regular is 85 so I have to buy mid-grade which is 87. In Michigan, where I grew up, Regular is 86 so I could use regular if I lived there. Why is there this disparity between different states? That’s what I would like to know.