And....there is nothing wrong with the fuel you are using. Whether it is Sam's Club, ARCO, Chevron, there is virtually no diff at all between quality of fuels, though there is a diff in the octane, which is stated on the pump. The only real quality issue for fuel is if you fill up at a station well out of the beaten path, and the fuel is very aged, or at the bottom of the tank being sucked through a poor filtering system.
There is a gas station in the middle of highway 95 here in NV that I have never once seen a customer gassing up at...I would hesitate to put that in my car.
Jim