I Have Bad Gas.

Really, I do or did. Ask anyone who was unfortunate enough to be down wind or behind me. It stinks. Now, I'm not proud of it but, I thought sharing my testimony would help those of you with a similar affliction. For years, I used Costco premium in my NSX and my S2K and they seem to have run well on it. However, recently both cars started throwing misfire codes. On my NSX, I started smelling gas, running rough and blowing coal on acceleration. People started complaining about my stench. My NSX is turbo'd, so my first thought was that the tune was way too rich. (Better rich than lean. But, this was ridiculous.) My local NSX Guru (Scott Oliver of HNA Automotive) pulled the plugs and all six were fouled. He replaced them with new plugs. The coil packs were good and the fuel filter was clean. So, before paying $700 for a tune and dyno, I decided to try some different gas. Scott recommended Exxon/Mobil, Shell or Chevron. I filled up with Exxon. Within about 100 miles of driving the car started idling a bit smoother, the codes stopped throwing and it was as if angels were flying out of my car's tail pipes.

As I said, I ran Costco for years with no issues and was certain their supplier was tier one. Either something changed or the bad gas just caught up with me. The fault was my own. I went cheap. Don't be like me. Use a tier one brand name "go juice" in your car and avoid the shame of a smelly rear end and performance issues. Have a little self respect....it's an NSX not a Prius.

Seriously, I've found that every time I try to save an extra buck on this fine car, I get disappointed. And it ends up costing me more in the long run. Sometimes it's the simplest of things that can cause significant problems. Like many of you, it's my dream car. So only the best is good enough. I use OEM Honda/Acura parts and fluids when possible and now good gas and oil in my baby. I hope that this sheds some light for those of you with similar problems.

That sucks. I run nothing but Chevron.

Interesting, I have been putting some Costco in lately because the price can't be beat and I generally trust Costco's quality standards, but maybe I should reconsider. Thanks for the heads up.

Wow that's a drag. Glad it's resolved.

Mobil, Sunoco or, Shell is what I use. I want to use as much as I can too! :biggrin:
Do you have Texaco down there? I figured you would, and their fuel was always good. Hardly any of those around here or they would be on my list too.

pbassjo said:

Wow that's a drag. Glad it's resolved.

Mobil, Sunoco or, Shell is what I use. I want to use as much as I can too! :biggrin:
Do you have Texaco down there? I figured you would, and their fuel was always good. Hardly any of those around here or they would be on my list too.

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Thanks Joe. Yes we have Texaco but, not many Sunoco stations. I always thought Costco was good for the price. But, sadly it's not good enough. Car flatulence is an embarrassment.

I mainly use, BP, shell or sunoco.. Whichever is closest to when I need fill up.

In Canada and I suspect the US, Costco is not a refinery owner / operator. In Canada, the smaller refineries have pretty much ceased operation and all of the refined product originates from the majors. So Costco has to source their product from one of the (former) seven sisters or other larger entities. I suspect the same in the US; but, perhaps there still exist some smaller refinery operations. The primary difference in the fuels may be the additive packages and changes in the mix of refined fractions that can alter the octane number. The majors may reserve this for their integrated or franchised retail operations.

You could have legitimately got a batch of bad refined product which may be a risk with even major refiners and their retail outlets. It is also possible that the fuel from the Costco retail outlet could have been contaminated. However, I expect that the turnover in fuel at Costco retail outlets is probably on the high end so the fuel should be relatively fresh. I tend to avoid the local budget price gas outlets because they all look pretty dodgy. Because of their retail volumes and what appears to be externally well maintained facilities, Costco is not one of the vendors that I would avoid. You need to do whatever makes you feel confident; but, I think writing off Costco as a gas retailer might be premature.

Full disclosure, I have never put Costco gas in my NSX; but, primarily because the Costco retail outlet is about a 25 min drive (one way) and I am not particularly motivated to do a 50 min round trip to save $5 or $6 on a fill.

I'm sure you car with the twins is more sensitive to fuel quality than say a bone stocker.

I've never had a problem using Costco Regular and Premium gas in any of my cars. When I'm not able to get to Costco I'll usually only use Shell, Mobil, or Chevron. I avoid filling up when a tanker is at a gas station. It tends to stir up any sediment that may be present in the tanks.

I've always found this questionable but don't know who has the correct answer. While most major brands, Chevron/Shell/Exxon likely refine their own fuels, where does the little guy and no name brands {Cosco, ect} get their fuel from? A short few years back I got my gas regularly at a small convenient store that sold Shell gas near my house. One day I got 5 gal in my can for my mower. As I poured it in it was clear as water. While it smelled normal it was literally clear. I called the dept of Agriculture to find out what was going on and they did an investigation. Turns out the store owner would order his fuel with no additives that are designed to clean/protect the engine that Shell raves about. He was selling raw gasoline to save himself a buck while charging retail. So where is the line drawn. That ended any small convenience store gas purchases for me. I was told also that many of these small stores would get caught running gutted pump filters.

davidf said:

I've always found this questionable but don't know who has the correct answer. While most major brands, Chevron/Shell/Exxon likely refine their own fuels, where does the little guy and no name brands {Cosco, ect} get their fuel from? ...

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Costco buys from the the big name gas companies that you mention and is a Top Tier fuel.

docjohn said:

I'm sure you car with the twins is more sensitive to fuel quality than say a bone stocker.

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I agree that could be the case. But it may have to do with the additives as well. But, both the S2K and the NSX are running much better now.

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DocL said:

Costco buys from the the big name gas companies that you mention and is a Top Tier fuel.

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I thought that as well. Maybe it's just this particular store. My NSX guru said he's had several cars in his shop with similar problems and Costco fuel turned out to be the problem. Don't get me wrong I like Costco. I just have two cars that don't run well on their fuel.

Interesting. I use Mobil '93 Octane 100% of the time.

pbassjo said:

Wow that's a drag. Glad it's resolved.

Mobil, Sunoco or, Shell is what I use. I want to use as much as I can too! :biggrin:
Do you have Texaco down there? I figured you would, and their fuel was always good. Hardly any of those around here or they would be on my list too.

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Joe have you tried Stewart's non ethanol? It's only 91 octane but I have been running it in everything I own. My NSX is not boosted but it's a noticeable difference in gas milage and performance even on the S/C vette. My NSX seems to love it. My mowers are always a pain to get started in the summer after sitting all winter even with STA-BIL added. The non ethanol completely solved this issue with just a change in gas.

davidf said:

I've always found this questionable but don't know who has the correct answer. While most major brands, Chevron/Shell/Exxon likely refine their own fuels, where does the little guy and no name brands {Cosco, ect} get their fuel from? A short few years back I got my gas regularly at a small convenient store that sold Shell gas near my house. One day I got 5 gal in my can for my mower. As I poured it in it was clear as water. While it smelled normal it was literally clear. I called the dept of Agriculture to find out what was going on and they did an investigation. Turns out the store owner would order his fuel with no additives that are designed to clean/protect the engine that Shell raves about. He was selling raw gasoline to save himself a buck while charging retail. So where is the line drawn. That ended any small convenience store gas purchases for me. I was told also that many of these small stores would get caught running gutted pump filters.

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That is cool you went through all that trouble to expose their shenanigans. I would have just ice grilled them as I drove by. But you went the extra mile!

DRIFTER said:

Joe have you tried Stewart's non ethanol? It's only 91 octane but I have been running it in everything I own. My NSX is not boosted but it's a noticeable difference in gas milage and performance even on the S/C vette. My NSX seems to love it. My mowers are always a pain to get started in the summer after sitting all winter even with STA-BIL added. The non ethanol completely solved this issue with just a change in gas.

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Same here. We have a VP station right down from me. Octane is 91 but Eth free. Comes from Louisiana. I run it in the NSX and my big mower.

Sorry to hear you had that problem. As pointed out; Costco relies on local suppliers and "is supposed to" be bringing in Top Tier gas from the same sources as many of fancier brands (Chevron, Shell, etc or in my case, Aloha Fuels). Glad to hear though that simply changing to a different gas brand was enough to fix it.

FF Drifter said:

Sorry to hear you had that problem. As pointed out; Costco relies on local suppliers and "is supposed to" be bringing in Top Tier gas from the same sources as many of fancier brands (Chevron, Shell, etc or in my case, Aloha Fuels). Glad to hear though that simply changing to a different gas brand was enough to fix it.

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Yeah Fred, I thought the same. It could be just this particular Costco. Which is too bad as they are sometimes as much as .10 cheaper than anywhere else. My S2K was running bad and throwing codes too. I switched gas on it also and the problem went away. Aloha, Ed.

Yeah I got some yesterday.

pbassjo said:

Yeah I got some yesterday.

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Your reply is a little vague. If it wasn't about gas.....Congratulations!

Costco gas is Top Tier. I use it with my Comptech SC NSX with no problems here in Las Vegas.
http://www.costco.com/gasoline.html