Is there a difference in Gas Quality in the United States?

Question

In the United States gas is becoming very expensive especially in places such as California. My husband and I use to buy gasoline from the Costco service because it is substantially less expense and since we have 2 SUVs because we believe in our children's safety we spend about $120 each time for a full tank at the pump. Around a week ago, my husband told me if we could fill up a Chevron because he believes that the gas will last a bit longer if we fill up there because supposedly they have better quality....Is this true? If it is, then what would probably be the best gasoline company to go to in California, preferably Southern California.

Answer 1

I spend a lot of time out of state and California gas ALWAYS gives me worse gas mileage.  

Towing a 5th wheel trailer I consistantly get 8 1/2 to 9 miles per gallon using California gas.  The gas I get in Utah, Idaho, Montana and Wyoming consistantly gets me 10 1/2 to 12 1/2 miles towing on the same trip.  

Same vehicle in California (not towing) consistantly gets me 10 1/2 to 12 miles per gallon.  In the 4 states I just mentioned I get between 14 to 17 depending on hills and speed.  

I also buy gas at an Indian Reservation in California (non California fuel) and it gets me the same as the 4 states above!

Answer 2

I've had people tell me all gas is the same and that may be to a point... different gas companies add different additives which will make their gas different. Now I cannot prove this but I will buy gas from one company and do seem to get better gas millage than another type of gas. Wish someone would do a good study and see if one type of gas is any better for millage than another.