My gas mileage has dropped from 50 to 43

Let me guess you bought your last tank of fuel from Sams Club, Wal Mart, Costco, or BJ's Wholesale club.

 

Not sure what the implication is, but no, ARCO.

 

I found these posts from another forum arguing about Arco gas.
The Consumerist Forums - Is Arco gas bad for your car?

 

Here is my main reason for buying Arco gas: (none of the others listed in the first column are available in my area)

These companies do not import Middle East Oil:

ARC0....................0 barrels
Sunoco...................0 barrels
Conoco..................0 barrels
Sinclair................0 barrels
BP/Phillips...........0 barrels
Hess.......................0 barrels

These companies DO import from the Middle East:

Shell.......................... 205,742,000 barrels
Chevron/Texaco......... 144,332,000 barrels
Exxon /Mobil............... 130,082,000 barrels
Marathon/Speedway... 117,740,000 barrels
Amoco...........................62,231,000 barrels

Citgo......................from Venezuela

 

while that is true, you have to understand that gas stations get their gas from many different places. its not as if an arco station ONLY buys gas from the arco facilities.

 

i experienced the exact same drop when ethanol was mandated into the gas here in oregon. past winters, i'd get upper 40s to lower 50s. but this last winter, up until last month, i only managed lower 40s. my last tank was filled in washington with non-ethanol gas, and i've been back to the lower-mid 50s.
i know that the ethanol blend is not supposed to lower my mpg so much, but there's nothing else that explains my situation. i watch my driving habits, routes, tire pressure, overall maintenance. nothing different there. no heat or a/c. even warm weather didn't help my mileage with the ethanol mix. hopefully, there is something i'm overlooking that i can fix. seeing a low 40s average makes me sad.

and i've only ever filled my prius with chevron or shell. out of some research i did a while ago, they seemed the lesser of evils among top tier gas available on the west coast.

 

I am in CA right now. I have been filling up at ARCO the last month because it is usually 10 to 20 cents cheaper, and I am also noticing a drop in my mpg's, down to 39 mpg from 45 mpg. It feels like ARCO is adding ethanol and not letting us know. Does anyone know if ARCO adds ethanol?

When I fill up in Iowa the pump is clearly labeled if there is Ethanol in the gas, and give you a choice of non-ethanol which costs 10 cents more per gallon, but I get 12 to 15% better mileage with non-ethanol even though the octane is usually lower, so that is what I use, even though it costs more.

For those of you in CA, what is the best gas stations to use to get the highest mpg?

 

It would be illegal for there not to be a "May Contain 10% Ethanol" label on the pump. Or maybe the delivery guy made a mistake; it happens.

By The Way, octane by itself has almost nothing to do with MPGs. When it does the car needs a tune-up :_>

 

Put 5 gallons in today at a Shell Station, reset the mpg screen, now averaging 51 mpg for 30 miles since filling up. Up from 39. Can't really explain that big of a jump. It was 87 octane BTW. I always get the lowest octane they have available, since you are right, the octane doesn't matter. I bet I go back to that Shell Station again though

I asked at a random gas station, if there was ethanol added to the gas and the attendant looked at me like I was some kind of an alien. They had no idea.