Costco Gas

I've been filling up at Costco in Tumwater, generally about twice a week, early in the mornings (7:30 am - ish). I'm not seeing much difference in MPG vs. filling up at Shell ("Top Tier gas").

Is there a difference, notable, in your commute vs the trip to Ikea?

 

I alternate between Costco and Mobil and can't tell the difference.

 

Engine warmup has a major mpg impact on short commutes, especially if you are using cabin heat in winter.

 

When I lived in CA, I somewhat frequently got gas from Costco but couldn't tell a difference in gas mileage from it vs. anything else. There are no Costco gas stations near me now, so I can't speak WA state Costco gas.

 

In 15,000 miles, I have had your experience twice -- and the variable was not Costco. I believe that any station is capable of receiving a "bad tank" of gas . . .probably with too much ethanol added.

 

Could it be summer vs. winter gas formulation. Here in New England, the stations all seem to switch to winter gas in early November and the hit on mileage is immediate. I usually see a 4-5mpg drop when I get a tank of winter gas. Occasionally during the change-over period, I'll get lucky and hit a station that hasn't switched yet but generally I just need to wait until April to ever see a tank average over 50 again.

 

I use Chevron, Shell, and Costco from stations in Oregon and Washington, I have never seen a difference in mileage or anything else due to the brand.

I do see a difference in winter vs summer and I think I get better mileage when I fill up in Nevada or Idaho due to a lower percentage of ethanol.

 

I've used Chevron, Shell, and Costco gas, and haven't noticed a difference in MPG.

 

use costco (60% of the time) + shell / QT (rest) and no difference.

 

It's likely just a "bad tank". OTOH, maybe Costco's suppliers are more variable, increasing the odds of a bad tank.

BTW, I'm still trying to get my head around 110 mile round trip to do a little shopping at Ikea. I know it's not unusual, some of my relations drive to neighbouring countries to shop, LOL, but...

 

We use Sam's Club Regular locally and ARCO Regular on trips and haven't experienced any adverse pinging, etc....

 

But your relations are probably driving only a fraction of that distance. Even Bellis Fair Mall is only half as far from Surrey or Langley.

 

Lets not forget Ethanol. If Costco
gas contains 10% Ethanol, you will get less
MPG than Chevron with no Ethanol.

So, my theory is that your Costco gas
had Ethanol, and Chevron gas did not.

Here in Oregon we have no choice. The state
government madates all gas for auto's be 10%
Ethanol by law all year long.

Ethanol is without a doubt the biggest scam
the government has ever forced down our throats.

Not only does it take 2 gallons of diesel to make one
gallon of Ethanol, which by the way has about 65,000 BTU's
compared to Diesel with 130,000 Btu's, but your tax
money is spent to give you less mpg.

Yes.... we loose both ways!!!!

al


.

 

My G3 is company provided, so I get gas wherever the card works. We don't have Costco, but there are a lot of independents that take my fuel card (including some 'corn-free', or E0 stations.) I haven't seen as much as 1 mpg difference in any gas that I've used....including gas that's (allegedly) E0.

Good Luck!!!

EDIT: All of our Chevrons are E10 (for now.) Some of the smaller gas stations claim to be E0 (trying to pander to the corn-hate crowd.) My tank averages vary as much as 5 MPG with temperature (+70 to +24F) but I just haven't seen a big delta with gas.
Caveats: I don't drive a set route, and I haven't separated the 5MPG deltas fully WRT temps and E10 versus E0 variances. Also...I only have 5,000 miles in type.
I’m sure the Scangauge crowd has better data on the “E” factor.

 

My daily commute is 112 miles round trip.

Then, on Saturdays, we will do the same trip for our shopping. Of course, we do it as major shopping trips, as in all the groceries, dry goods, pet food, etc. We'll throw in visiting friends while there when possible, and probably a meal out.

 

I find it highly unlikely that his Chevron gas did not have ethanol.

And if it didn't, plenty of us who like 'real' gas would like to know about it.

 

Gas is all the same, only the distributors are different.
Costco uses BP/Shell/Exxon or whoever sells it cheapest.
I regularly use WAWA gas and have never noticed a difference between that or Shell/ Exxon, Valero etc..

 

I have stated this in other posts. But I have experienced a difference in gas quality, between the cheap stations and brand names like shell. When I owned a '96 Chevy Lumina, I found out the cheap gas was giving me engine issues. It wasnt until I switched to shell, that I no longer had the engine issues. So, I will no longer use the cheap gas, unless I absolutely have too.