My mom was told by costco gas people that they get Chevron gas now, it used to be something else though.

 

Costco is like Sam's club..Sunoco gas is usualy great..Sunoco i belive does all of the nascar fuel and a lot of drag super high octane (not nitro or alcy)

 

IT IS THE GAS....in my opinion of course....I kinda read the first post and skipped the arguement....but here is my personal experience with Costco gas....

Now I used Costco two times in my S-10 years ago. Since I'm anal about MPG I reset the trip every time. I filled up my S-10 at Costco in MD and got about 50 miles less then I usually did, I thought maybe I was a little heavy on the gas. I then filled up on Exxon later that weak and got the normal MPG I was getting before. The following weak out of curiosty I went back and filled up, once again 50 or so miles less then I usually got...So I said I'm never putting Costco gas in anymore, no wonder its so much cheaper.....

THEN two years later, I've sold the S-10 and own a WRX. My girlfriend gets into a fender bender and I let her use the WRX while I drive a company vehicle. She calls me at work and says, your car is doing something weird. I tell her to park it and dont touch, because if it breaks I want to be the one to break it. The WRX is heavily modded in my opinion (STI Injectors, VF34 Turbo, Perin Turbo-Back, APS Uppipe, Walbro Fuel Pump, Cobb Stg 2.5 map, blah blah)...So when I get home I start it up and drive around and its having audible detonation....which it NEVER had before I mean I'm running 2000 bucks in supporting fuel mods....I asked her when it started and she told me 20 minutes after she got gas. I started to get upset and she assured me she put in high octane. Then after talking to alot of people, including the guys at Cobb Racing, I ended up dumping a ton of tolerene <sp> in the tank and changing maps, that it kinda cleared it up. Once it was empty I filled up on Exxon fuel again, changed maps back and it ran like a champ.....later to find out she got the gas at Costco, I never thought to ask at the time. I just figured she got a bad "batch" or didnt realize she put in regular instead of premium....

Thats my experience with Costco Gas.....

EDIT : This also leads me to another thing. My uncle owns a Citgo service station (Danny's Service Station in Havre de Grace, MD if anyone is familar). He stop being a Citgo dealer because he said he was only making pennies on the gallon and that did include pump maintance or electric. Now costco is like 10 cents cheaper in the area which means one of three things. Costco is loosing money on gas sales, unlikely. Costco gets gas cheaper since they sell millions of gallons, possible. Costco buys cheaper gas, also possible. Just wanted to throw that out there.....

 

Thats a classic sign of cheap gas....It happened to my father once in his police car using a baracks gas station....happened to about 30 cars that winter because the state police were getting the gas from the cheapest place they could find it....

 

she assured you that she put high octane in it.. most women dont even nkow what that is!!!!! i bet she tried to save money and put the cheapest gas in she could find... then lied about it later to save her butt....

i would have doen the same thing


anyways, there are some very dishonest places out there, and if they do water down the gas, its very easy for it to not get what it supposed to mileage wise.....

 

There is a reason for the variation in gas prices from company to company. They are not all refined in the same place with the same methods. And it appears that the more engine mods you have the more obvious this becomes.

 

Ok, here's the deal with ALL gas.(I have a friend that does sales work for the refinery in our area). The base gasoline is made at a refinery. Each gas station has their own spigot per-say at the refinery. Their truck comes up and fills up with the same gasoline as everyone else, but each spigot has different additives. So, yes, same gas at each place, but their additives are completely different and have a big impact. Some additives are just filler, they don't do anything more than water down the gasoline. Others are benificial and make your engine run better. So... depending on what they add, the gasoline at one place could make your engine predetonate while another gas won't.

To tell you the truth though, running one tank at a time of each gas will not give you a good baseline on the performance of the gas. You'd need to do more like 5 tanks, then 5 tanks of another, etc. I've done that before with several different gases and several different vehicles. Found that Arco is complete crap, my trucks would ping with their gas. I think 76 and Chevron are the two best. But anyway, I was told by someone that works for the refinery, NOT to buy the cheap Arco/USA/non branded gas. He has nothing to gain. He makes money no matter who I buy from.

 

I did this same test here in SC with my Tacoma. Everytime I got better gas milage with Hess and everytime I got the worst with BP.....Only by 20 miles or so in the end.....

 

I live in cali and have a S/C. I filled up at costco for a while and noticed a lot more ping. I now use Chevron and hardly any ping at all. I've also tried 76 and noticed a little more ping as well. It's been about a year and a half since I have filled up at Costco though so I am interested to see if they really do use Chevron Gas. I drive by costco everyday so I will keep my eye out.

 

i will vouch for the chevron and say that they do have techron in it, which is a blend of stuff, but its mainly fuel system cleaner, and that always helps out

 

Cosco and Sams buys gas from whoever is cheaper. They dont have to buy from one company. Companys put their own "additives" in "their" gas. I'm sure both Cosco and Sams get whatever is cheapest. I try and use Citco or Exxon. I wont use gas from mongrel stations.

 

It's not always the gas it can also be the gas station old sttions with crappy tanks allow moisture to get into the gas, and no jim you can't add water to gas to make it cheaper, you can add other chemicals (alcohol) to it but you're not allowed to add water to commercially available gas, it's very illegal. And yes the gas is generally the same as it has to meet national requirements for octane etc but companies add things to the gas to make it run cleaner, better etc. (Chevron)

 

It's really interesting hearing all this, and hearing the various different gas station names. I'm not exactly sure how relevant this is, but one day I was at our local Amoco (which I swore always had the best gas in the area for my 89 IROC-Z and HEAVILY modded 87 turbo Regal).... and as we know BP bought them out but the signs all brag they still have Amoco fuel... anyway, there's a guy walking around with a little red wagon and some jugs going from pump to pump. I couldn't figure out what the heck he was doing so I went and talked to him. Turns out the government shows up randomly at gas stations and does a whole bunch of measurements on the gas sold as well as the pumps. He would pump a gallon of gas, and then varify that a gallon actually comes out. If I remember correctly he was also testing the octane levels for accuracy too. So, that being said, the government is keeping tabs on it. However, I still do believe there are better gases than others. For us, the Casey's gas station chain that is common has always been known to have junk gas, and from my experiences it is true. For what it's worth, DON'T support any Costco, Walmart, or Sam's Club gas. I won't get started on how much I hate Walmart, but think about how they operate: They undercut everybody else on prices with the plan on running them out of business. Once this is done they are free to jack up the prices and run a mini monopoly. So how do you undercut gas prices when there is a profit level of less than 10 cents a gallon? Obviously, you've got to be buying the absolute cheapest sh#t gas you can find. I've my own decisions, I'll let you make yours. Wow I get worked up when talking about Walmart!!