Im certain they are selling regular fuel from their premium dispensers. I have a cadillac that requires premium fuel, and when i put regular fuel in it has to retard the timing so much that it starts quitting at stop lights and lurching at low speeds.
On may 23, 2010, i was on empty, put 40.07 of PREMIUM fuel in, and less than a block from the gas station my "service emissions system" warning came on, check engine light came on, and started lurching under 50kph, when i was nearing my destination that evening it QUIT at 50kph as i was leaving the freeway in the south end of calgary.
I fixed this by adding OCTANE BOOSTER, to make up for the difference in octane, which reduces pinging in high compression motors, which if was sufficient, would not have been needed to compensate by retarding the timing in my car so much it began quitting on freeways!
This happened previously when i put in midgrade fuel at a small fas gas station, but by simply topping up my tank with premium at a petro canada, my codes cleared within hours and the car began behaving normally.
Im looking for more ways to lodge a complaint, really, who knows if they are getting what they pay for at the pumps. Anyone else have a vehicle that tells them its not premium? This is an eye opene