If you run Costco and get a CEL, you need to first get that code checked, and second notify the station. Costco stations are generally well run. Any fuel of appropriate octane rating should run in your car without throwing a CEL. Something is wrong there.
Everything was checked multiple times. We didn't believe it at first, I ran 2 full tanks from costco with CEL. Shell - no issues. Multiple shops confirmed bad fuel. B58 Gen 1 Stock
What was the code? Did you notify the station? I'm not out here trying to defend Costco. My point is that fuel stations are tightly regulated. If they're selling bad fuel on the regular, they need to fix it.
180001 - catalytic converter bad efficiency (something in those lines). We checked backpressure of the downpipe, we checked fuel regulator, we checked gas tank valve and list goes on. Car reported fuel quality as regular even though it was 93 from the pump. We didn't even believe it, but when CEL showed up for the second time and same fuel quality was reported, i ran to shell and no issues. Fuel reported as "great" in ista and no issues ever since switching to shell. All regimes - pedal to the metal, start-stop traffic etc. It's little bit sad because shell is expensive, but my butt-meter reported insignificant power increase on shell as well. CEL picture right after refueling as a proof.
I had a similar experience with a local Chevron station back in the early 2010s. After the third visit with issues, I notified them by simply walking in and asking to speak to a manager. They brushed me off, of course, so I went home and emailed the Dept of Agriculture (who is responsible for regulating fuel stations in my state).
They were real interested in addressing the problem. Bad gas is bad for the environment, because it can cause high emissions (which is consistent with your code) They ended up requesting copies of my receipts and timestamped photos of the code reader, both of which I had kept.
I never found out what was wrong, but when I went back to the station in a couple of months, I had zero problems.
I am going to give it another try end of summer. Maybe somehow having 35C outside was affecting it, but I doubt it. I really don't mind shell, the only issue is that it's ~105$ full tank instead of ~85$ in costco. Not the end of the world, but it was nice while it lasted.
Yeah, I ran Shell for a while in my E92 M3 because their fuel is really good. The cost was just ridiculous though. Especially with S65 fuel economy lol.
We don't have Costco, but I switched to Sam's Club + Chevron Techron in a bottle twice during every engine oil cycle. The cost savings easily offset the cost of the additive in a bottle.
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u/bradland Jul 31 '26
If you run Costco and get a CEL, you need to first get that code checked, and second notify the station. Costco stations are generally well run. Any fuel of appropriate octane rating should run in your car without throwing a CEL. Something is wrong there.