Hi,

First, TheSpoils, tier 1 has nothing to do with octane rating. Tier 1 is a marketing scheme where several companies agreed to sell gas at a certain purity with a certain cleanser additive that supposedly gives greater gas milage. This is in all grades of gas. I have seen a slight difference in Shell gas over the others, but on the whole I have not seen much of a difference among quality name brands. There is more then one refinery, even in NJ.

Second, Marianne, individual stations may be privately owned even if they are part of a franchise. They may have older equipment that, as TheSpoils mentioned, may not give as pure a gas as others. Cheating does occur, and you should not go to a place you can't trust. Be aware, however, that just because a place is listed as tier 1, it does not mean their gas is better, it just means their parent company agreed to be in that group and sell that gas.

Also, many cities and states mandate additives like ethanol at certain times of year. Tier 1 is only based on gas based on the standard. If ethanol is mandated, then that gas no longer meets the tier 1 standard even if it is sold by a tier 1 station. This would not be their fault. My entire State (NJ) has additives in all gas at certain times of the year, but where you live it might be by area. Your station at home might sell better gas then the same name brand station where you work, because it may be in a different zone.

Tier 1 gas is mostly marketing. Companies are constantly coming up with new ways to keep more of our money. (Remember when self-serve was supposed to save US money.) Find a station with a consistent quality that you trust and stick with them.