Have you tried Chevron 94?
funny thing is that my car doesn’t run well on Shell,Petro or esso fuel. I don’t know why, but I know we get our fuel in BC from a different refinery than in Ontario. My sonic (stock as heck) only runs well on Co-op 89+ gas, or Chevron mid grade + gas. What I found out later, Chevron and coop use the same gas and detergent mix, which is why I wasn’t able to tell the difference. And co-op 91 doesn’t contain ethanol as well.
