Do more expensive brands of gas get better fuel economy?

Do brands of gas that charge on average 20 cents more per gallon get more miles per gallon than off-brand gas stations or ARCO?

I went to the Honda dealership today because I noticed I was only getting about 21-25 mpg in my 2008 Civic, rather than the advertised 25-30. The mechanic said that the reason that I got poor fuel economy was because I bought gas from the least expensive places, such as USA Gas and ARCO which we, on average, 20 cents cheaper than Shell or Chevron. He said the refining processes for these places’ gas was different and that if I filled up at one of the more expensive places, I’d get better gas mileage. He also said that neither were better or worse for the car and that it’s likely that 20 cents cheaper per gallon would still be more cost-effective than getting a few more miles per gallon.

The only difference between the off brand gas stations and the major brands is the major brands are likely to sell Top Tier gasoline.


Find a new mechanic. Gasoline is delivered to terminals from the refinery. The terminals store every retailer’s gasoline in the same tanks. Tanker trucks pick up the gasoline at the terminal and delver it to the various gas stations you see. Exxon, Shell, Gulf, BP, ARCO, Hess, USA Gas, and any other you can think of all come from the same tanks at the terminal. The additives that a particular retailer uses are put into the gasoline after it leaves the terinal storage tank.

Except for the additives, it’s all exactly the same gas.

Only major difference is amount of detergents

Nope! You’re wrong.

The tanker trucks get their gas from the same terminal. But when the tanker is being filled is when the gas, ethanol, and additives are blended in. Then the truck drives off with that blend.


Tester- look at my edited version - that’s the major difference, right?



Your driving habits has bigger effect on your mpg.

Nothing wrong with ARCO, The PNW refinery uses mostly Alaskan-USA oil, but not always. Alaskan oil, by law, must be refined in USA. Maybe the bad gas is Alaskan?

Gas feedstocks are the same regardless of the oil.

Nothing wrong with West Texas Light. I see that the spot if WTL is down considerably this week.

I doubt it. We have an mpg meter in two cars and have not noticed a difference between brands.

I can get non-ethanol mid grade for a dime more per gallon than 87 with ethanol. The mileage difference is about 1 mpg in about 30; makes the extra dime worth the price. It saves a good part of a dollar (almost nothing) per 1000 miles at 3.60 vs 3.70 per gallon. If there is a brand that gets better mileage, I’d like to know about it.

When did you notice this? Winter blends in many areas use different formulations that reduce gas mileage. I know it’s late in the season, but if you noticed this a few months ago, it might be the reason. If your gas mileage mysteriously goes up soon, it will be the summer blend.

If your fuel mileage has really dropped off that much, then it seems to me that the mechanic should be suggesting more viable reasons why the mileage has dropped. That would include engine state of tune, tire pressure, possibly slipping transmission or clutch as the case may be, etc rather than a cheap gas explanation.

A brother in law in Texas delivers gasoline and he would probably disagree with the mechanic also.

Gasolines have to meet certain Octane standards; refineries run different grades, then sell them to distributors who specify the additive package. The refiner will sell this same gas through his own stations and have his own additive package. Anti-icing and detergent additives are the most common.

So-called top tier gas has all the necessary additives and then some. Most cars don’t need all those additives.

I tank either from a top tier supplier since they have a good car wash, or from the local Co-op, who gives me a discount, but has a poor car wash. Both gasolines work well in our cars. Oil companies also swap gasoline; depending on their inventory. It will be delivered to the station by an independent truck without any oil company logo on it.

We always advise not to tank from a station with very low sales volume, such as “Joe’s Bait & Tackle” in the Ozarks. Even good gas will turn skunky in Joe’s tanks.

Let me guess…you were talking to the repair service representative, the guy that does the paperwork.

All gas station in a region use gas from the same stock…the same exact pipeline even. Different brands use different additive packages, but these packages are derived from long-established refiner’s labs and very undetectably. The only time more expensive gas will bive you bettr mileage is IF you’re driving a “boosted” vehicle (you are not) that requires premium octane and you try to cheap out and use regular. In those cases, he engine’s ECU will actually “detune” the engine to prevent pinging and preignition.

Now, tell us about your Civic. How many miles does it have, when was the last “tuneup”, are there any operating symptoms, what’s your driving environment like, and what are your driving habits like?