Costco sold me bad gas

Try to get behind the car that uses premium gas,
There aren't any!

So you walk the pumps and look at the total in dollars and gallons to determine who pumped premium? That's dedication! :unsure:
Well here's the thing, sometimes I'll only top off like 3 gallons or so, and bikes, unlike cars, aren't required by law to handle all flavors of gas (no VVT). I put midgrade in once, and immediately got knocking.

Just because the above ground gas station takes a lot of real estate doesn't mean much for the underground storage tanks. I'm confident they right-sized it. You could probably scrape up real numbers from the fire permits or town GIS data.

They don't "need" bigger than maybe a semi-trailer and a half to get their best pricing. Their 87 octane is likely bigger still so they can get gas at the most logistically relevant times-- times that don't interfere with customers in line to fuel up. For all we know the fill hole could be well off to the side so the trailers don't bock traffic. As you say, there's lots of real estate devoted.

Honestly it sounds like you got water in your gas that the ethanol coagulated with. The question is where did this water come from, was it pumped or did you somehow get rain water, vandals etc in your tank after you bought it? Costco should have a water in-tank warning device and/or separator at the dispenser.
It wouldn't surprise me at all if they screwed up their calculation, because of exactly what mr. slack said:

Costco has a disproportionate amount of affluent customers, so even the premium will sell quickly.
That's not the case over here.
 
Your username had me thinking only of Kentucky, which would also align with regular fuel cars and HFs.

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They do, right?

Like I said, my suspicion is the tank they use is too big for the area (they have an impressively large gas station), but nobody here tanks premium gas. I know this, b/c I will sometimes do the "fuel pump walk" where I check each pump and do the mental arithmetic to figure out if the last guy put premium gas or not. I do this b/c I'll sometimes refill the bike with only 3 gallons, really close to the minimum dispensing amount. I'd say the number is significantly under 10% for premium gas... and I also imagine costco is used to a clientele who more frequently tank premium. That and the overwhelming summer heat... I suspect I got the dregs of the oversized premium fuel tank, which was mostly water.
I thought the gas went bad?
 
I’m wondering if the high detergents in their premium loosened up some dirt or crud in your engine. Go back and talk to one of the attendants and feel them out about if they got a bad load of gas.
 
What did you do with the bad gas. If it was water it should separate out of solution when it sits for a while?

My dad got a tank of water from a very busy station decades ago. His was regular not premium. We didn’t believe it could happen either till the tank was drained.

No corporation would admit to it even if they knew - especially not a Fortune 500. The publicity would kill then.
 
Gas stations hate to admit problems with their fuel but it does happen. A few years back I stopped and filled up at a local station and was lucky to get home my truck was running so bad. Cracked open the fuel rail and it was obviously a water problem, you could hardly smell any gas. A few minutes later the lady next door came over and asked if I could look at her car. Sure enough she stopped at the same gas station on the way home. A few bottles of water remover and a few bottles of rubbing alchohol took care of the problem.
 
I’m wondering if the high detergents in their premium loosened up some dirt or crud in your engine. Go back and talk to one of the attendants and feel them out about if they got a bad load of gas.
That was my thought. We had a 2010 Jeep Wrangler that ran poorly on the first couple of tanks from Costco. After that it smoothed out.
Too much crummy Speedway gas before the Costco fan boy gas that I now use :cool:
 
That was my thought. We had a 2010 Jeep Wrangler that ran poorly on the first couple of tanks from Costco. After that it smoothed out.
Too much crummy Speedway gas before the Costco fan boy gas that I now use :cool:
If it’s the same area the Costco gas comes from the same terminal down the same pipe. Only possible difference is the add pack.
 
Op - did you save the 'bad' gas ?

Maybe get a Gasoline Ethanol Testing Kit.
This will show you how much ethanol (and water) is in the gas
.
https://www.amazon.com/REV-X-Super-...hy=104984&hvtargid=pla-4584207577604364&psc=1
And a Gasoline Mr. Filter.
This will filter out any water. I have one and they do work.
(to test, you pour water into filter, and nothing comes out).
https://www.amazon.com/s?k=mr.+funnel+fuel+filter&adgrpid=1346902525250927&hvadid=84181633323031&hvbmt=be&hvdev=c&hvlocphy=104984&hvnetw=o

Save your receipts.
If you have 'bad' gasoline, test it at home and see if water is present.
Filter the water out into a glass jar and go back to Costco.
 
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I'm sorry you had a bad experience, and not saying that you didn't get bad gas, as that is certainly possible. However, there is no way to know for sure, and it's not in any way a knock against Costco if you did, given the rarity of such a thing vs. the millions of satisfied customers who never, ever get bad gas there.
 
Probably vapor lock. You mentioned it was hot as blazes. Costco moves WAY too much fuel to have enough time (especially when it’s hot) for enough water to absorb into the ethanol.

If anything, a little water in the fuel cools combustion and will “steam clean” some of the carbon deposits in the chamber and on the piston top.

Glad it was resolved. 👍🏻
 
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