Arco gas - mileage poor
 

I've always believed that gas is gas. However, I can help but notice that everytime I have used Arco gas, my mileage has been less. It's not once or twice. The last 5 times I've used it, it's been quite noticeable. Also, the point where my fuel needle hits when I have gone 200 miles is significantly lower when running on Arco gas.

Am I crazy? I've been trying to be as objective as possible and there is a trend for me.

jbum -

When I used to use Arco on my CRX and then my Saturn Coupe, I used 91 Octane and didn't notice any problem. But I wasn't tracking my MPG back then. However, my friend told me that Arco gas hurt his engine (can't remember the details, maybe just fouled up the injectors or ran terrible i.e. pinging). I know he wasn't using 91 Octane, so I am thinking that because I always bought the 91 Octane, I never had any problems. On my friends advice I stopped buying Arco in the late 1990's.

All this was before BP bought Arco. But I haven't gone back.

CarloSW2

maybe it was the winter mix or something. i used arco gas alot when i was in seattle and it never affected my mpg on all my civics that i owned. the only bad thing about arco in my experience was paying cash. it charged when i used debit or credit

Might be an individual Arco station that has something accumulating in their tank.

Really? I always got fine mileage with Arco stuff. Just goes to show you that it all depends on the car. There's a gas station here that always got me great mileage on my truck, but the next vehicle I got hated that same gas.

Not the manufacturer
 

Gas is gas, but some factors: Last time I had big problems in Long Beach, CA - a couple years ago just after a horrible storm. Got gas at 7-Eleven, the car would barely start after first time (before it started using the new "gas" in the tank. Thought is was "bad gas" - went to a Shell and filled it up, no more problems...seems water had seeped into the 7-eleven underground tank....:banghead:

ARCO is fine unless your car is HO and needs premium (although, believe it or not, when I was 20 and had a GTO with 11-1 compression ratio, it HAD to have primo. Nowadays, somehow they get 11-1 running on REGULAR UNLEADED. I don't know how, but I swear, look at the manufacturer web site, some engines (like Ford HO engines) say 11-1 compression ratio and REGULAR UNLEADED....

No, gas is not gas. There is always - not good - reason, something costs less. It's common sense wisdom, and you can argue it to death, it does not change what it is - common sense WISDOM. And as such, it should be listened to.
Arco, CircleK, AM/PM - all those cheapo brand stations will NOT improve your gas mileage and in long run, will cause harm to your engine, unless you continuously prime their gas with additives like STP or Seafoam.
But then, what is that you are saving by spending more on them?
Also, you have to keep in mind one thing: all modern cars have ECU/ECM that has learning feature built in. As in - it is continuously monitoring data coming from all sensors and continuously adjusting power train operation to optimize it. Hence, if you stick to same gas and even same gas station, you have your power train optimized to its best for that particular set up. Flipping stations only makes it worse.
That needs to be remembered when any components replacements are done on power train, like sensors, air filters, etc. As engine changes its modus operandi and ECU needs to adjust also. Pulling ECU fuse for about 10-15 minutes clears "learned" mode and ECU re-learns new component.
Sticking to same gas station is no more than simple basic planning, which should be diligently done by any mpg conscientious driver.
https://i42.tinypic.com/10zs9ys.jpg

Gas is NOT gas!

On my supercharged Buick, where Octane is crucial, I can tell for sure when I go to a "cheepy" station. I can hear the engine knock and/or misfire. But when I go to a "real" gas station (that refines their own gasoline and pays attention to quality), there is a distinct difference in how the engine runs.

I tend to stick with Exxon/Mobil, Shell, and Sunoco only - leaning toward Sunoco whenever possible. And I watch for who is putting off-brand gasoline in their tanks (although you can usually tell from the station, whether they are "cheapo" or a legit station).

Some gas stations use more ethanol in the gas than others, typically 10% to 15%. Ethanol is less energy-dense than regular gasoline so it'll reduce mileage a bit.

I would say gas is gas more than people think it is. Arco is BP, but is there any sort of change with a different name?

Also, with more expensive fuel is the cost offset by improved fuel economy?

I've been working with my 2000 Outback a few months and only have run Arco due to cost. To get a good average I'd have to use another brand and try it with multiple tanks to see if there are any differences.