Costco gas

[agog]

Hi,

I just filled up a tank full of gas at Costco. Instantly noticed that:
- car was showing increased MPG by about 2mpg
- engine sounds harsh, looks as if engine is holding to a lower gear longer or something similar as engine noise has increased

Has anyone else experienced this? My car is less than 2 months old with <1000miles on it. Before Costco I filled up at Shell.

Thanks.

 

[paris1]

Costco is "top tier" gas that I've used almost exclusively for 20 years or so with nary a problem!

 

[inlinev]

I don't see the connection. Could be anything.

 

[Kedis82ZE8]

I've run a lot of Costco gas in my CX-5... no issues experienced.

 

[dergibog]

I use Costco gas exclusively and no problems here.

 

[Sekmor]

Even up here in Alberta, Costco has a good rep for good fuel. Don't use it exclusively, but have filled up the car/truck over the years and never noticed any issues.

 

[robertmazda]

I don't think that the gas increased your mileage. If it were that simply everyone would be using it. Costco and Shell are both sell top tier gas so there's not likely to be that much of a difference. 2 MPG could easily be explained by slightly different driving style, terrain, etc.

 

[dragonteeth]

I always use Costco gas... no problems.

 

[GP 2004]

I've never had a problem with Costco gas. I buy it whenever I'm nearby.

 

[MidwestCX5]

I occasionally experience a similar issue where the engine is noticeably less powerful/responsive after fueling up, but I think it has more to do with the quality of the gas station than the brand. I usually use Exxon gas because it is the most convenient and I have never had any issues with the quality. I also frequently use Speedway, Shell, Meijer, Phillips 66, Marathon, and Sunoco gas with no issues, but I have had performance issues after fueling up at some (not all) Kroger, BP, Sheetz, and Circle K stations. Additionally, the dealership recommends CX-5 owners have a fuel induction service every 25,000 miles, but I have not had this done.

 

[agog]

Update from my side. All the observations faded away after a couple of days and I am back to lower mileage with usual sound (hope that I have not accustomed to the raised levels ). This thread can official be closed now.

 

[Latitude Adj.]

I've noticed when I wax my car it gets better mileage ,sounds better, rides quieter and gets more smiles from young ladies

Your results may vary!

 

[ruthrj]

Bringing back a very old thread as the title is, well, perfect lol.

I didn’t catch this last year, supposedly Costco has reformulated all grades of fuel to prevent intake valve deposits on both port and direct injected designs. Don’t ask me how effective it is or how valid the claim may be but it’s interesting.

BITOG for short discussion:

https://bobistheoilguy.com/forums/threads/costco-upgrades-top-tier-fuel.382461/

Costco advertisement of change:

May 2024, Page 9

Possible formula they switched to based on permit request from 2023? Permit states a switch from Lubrizol 9888 to GA9058.

https://www.sdapcd.org/content/dam/sdapcd/documents/permits/public-notices/Costco-7920-Engineering-Eval.pdf

I’d be very interested to know if the new Lubrizol additive has friction modifiers for the top end of the piston like Shell does. Would be first gas I’m aware of that would give that benefit on a lower octane gas. I’d really like to see the safety data sheet for the Lubrizol products to see if they list compounds but access is only for registered users.

 

[Jmaz]

Last year when gassing up at Costco I chatted with the pump attendant. He pointed out 2 additional tanks and said that Costco has double additives in that they put in a second additive beyond what's already in the gasoline. This must be the Lubrizol. Perusing the third document linked above, there's mention of PEA which is used in some injector cleaners. I remember Lake Speed Jr. mentioning PEA in a video but don't recall if in addition to being an injector cleaner it was also effective as a gasoline additive for removal of piston ring deposits.
My car always runs good on Costco 87. Thanks for posting this info.

 

[GTXT23]

Hi,

I just filled up a tank full of gas at Costco. Instantly noticed that:
- car was showing increased MPG by about 2mpg
- engine sounds harsh, looks as if engine is holding to a lower gear longer or something similar as engine noise has increased

Has anyone else experienced this? My car is less than 2 months old with <1000miles on it. Before Costco I filled up at Shell.

Thanks.

I prefer a mainstream brand which I stick with and had used Costco prior with what I noticed as a slightly rough idle - which went away after I switched - both are top tier 91 - so if you like Costco use it - but ....im not certain how on a vehicle with under 1k miles you " instantly " noticed a 2mpg increase in gas mileage ? - that im skeptical on -
enjoy the new ride -

 

[paris1]

You do know you’re responding to a ten year old post?!

 

[GTXT23]

You do know you’re responding to a ten year old post?!

yes -belived since it was in " new " and the data is still relevant - it might be read by others -

 

[jadmt]

I prefer a mainstream brand which I stick with and had used Costco prior with what I noticed as a slightly rough idle - which went away after I switched - both are top tier 91 - so if you like Costco use it - but ....im not certain how on a vehicle with under 1k miles you " instantly " noticed a 2mpg increase in gas mileage ? - that im skeptical on -
enjoy the new ride -

Costco gas west of Mandan ND is supplied by Cenex and according to my buddy who ran the bulk plant said Cenex has the highest standards of any Gas company in the US. he said every company runs gas thru the bulk plant and Cenex was absolute sticklers on additives and octane. he said they tested all the time and Cenex octane had to be higher than advertised or he said there was hell to pay...he did not know what happened east of Mandan but said he would be surprised if it was not the same as he said the farmers wanted the best....

 

[GTXT23]

Costco gas west of Mandan ND is supplied by Cenex and according to my buddy who ran the bulk plant said Cenex has the highest standards of any Gas company in the US. he said every company runs gas thru the bulk plant and Cenex was absolute sticklers on additives and octane. he said they tested all the time and Cenex octane had to be higher than advertised or he said there was hell to pay...he did not know what happened east of Mandan but said he would be surprised if it was not the same as he said the farmers wanted the best....

I have no scientific evidence showing costco gas is anything but what they still state -( even 10 years later ) - but what i do know in my state ( as most others ) theres are 2 main distribution locations which serve all vendors - the drivers submit a profile or card when fueling which specifies which additives they will add - like an a la carte menu at a restaurant - - Some get more additives others far less - but 5 years ago I was running Costco 91 - on a new CX5 and swapped to a main brand and the rough idle went away - I could have been a bad batch or just a pcm kwerk that went away and nothing to do with the fuel - so thats just what happened - Use Costco if you like it !

 

[Jmaz]

I have no scientific evidence showing costco gas is anything but what they still state -( even 10 years later ) - but what i do know in my state ( as most others ) theres are 2 main distribution locations which serve all vendors - the drivers submit a profile or card when fueling which specifies which additives they will add - like an a la carte menu at a restaurant - - Some get more additives others far less - but 5 years ago I was running Costco 91 - on a new CX5 and swapped to a main brand and the rough idle went away - I could have been a bad batch or just a pcm kwerk that went away and nothing to do with the fuel - so thats just what happened - Use Costco if you like it !

I posted above that my car always runs good on Costco 87. I didn't think to mention the one time I used the high test (thought it is 93 instead of 91). It ran "OK". Rather surprised. Never bought it again. Like the 87 better. Now Costco gas here is supplied by Marathon whose gasoline, over the years and long before Costco appeared and wherever purchased, has always ran good in different cars. The local Marathon station 87 and 89 run better than that one tank (not exactly a big sample) of Costco high test. And the price difference is a deterrent also.