Your Brand of Gasoline Makes a Performance Difference?!

[flyn high again]

The Mobil station where I gas up my cars and trucks recently switched over to become a Marathon station. After listening to the owners promise me for weeks that Marathon gas was just as good as Mobil, I filled up my Cobra tank with Marathon Premium two days ago. I told them I would try a tank and let them know.

Well, so far in two days my car has died twice. Both times I was at highway speeds and slowing for a stoplight. It is exactly what people report when they talk about the "stall" problem. My car has only died once before while driving in the entire year+ of ownership and that time I hit the gas before the car was completely warmed up and then stopped quickly. Now with the Marathon gas and a warmed up engine, it dies twice in two days. I will give this tank of Marathon gas a couple more days to see what else happens but I am sure I will be looking for another Mobil dealer to fill my car up at in the future.

It makes me wonder how much of the stall problem can be attributed to what brand of gasoline everyone uses. Gasoline brand MAY be a contributing factor in some of the stall cases.

 

[WraithCobra]

I've only had two stalls in the 13 months/7600 miles I've owned the car. They both happened on the same day, the first happened with the clutch disengaged as I was slowing to a stop and the second within a few seconds after I restarted it. I always considered that my driving style, down shifting & clutch engaged until almost completely stopped the reason for my infrequent stalls, but maybe the fuel does have something to do with it. My records show 78% of my fuel being Mobil/Exxon and the other 21% being Amoco/BP, 1% being the unknown first tank full when I bought it. My intake is stock except for a K&N drop-in and removing the fender tube.

 

[kaboom]

Sunoco 94 only over here.

 

[flyn high again]

You guys both use decent brands. I had some bad experiences with Marathon gas decades ago when the mildly modified Camaro I owned would run rough after filling with Marathon. That made me hesitate to use any gas other than Mobil, Shell, or Amoco. I wasn't thrilled when the station I've used for over 10 years switched to Marathon last month. It may just be coincidental but I find it strange to have two stalls in two days with a completely warmed up car. That's definitely not normal for my car. Unless something has suddenly broken with the car [which I doubt], the only difference in the last couple days is the full tank of Marathon gas. I will run through the rest of the tank and see if it stalls again. Then I'll switch back to Mobil and see what happens. :shrug:

 

[NHRACobra]

I use nothing but Sunoco 93. They stopped selling Sunoco 94 in New England.:mj:

 

[mike79]

I use Sonoco 93, but tried Amaco 93 this time. So far I love it. Car feels great. Runs great too.

 

[LCCOBRA]

Originally posted by kaboom
Sunoco 94 only over here.

:thumbsup: It's worth the extra loot...

 

[BenD]

Talk about bad gas!

I think the worlds worst gas is what we get in Colorado. Fortunately we now have shell stations and mine runs decent on shell. But we do have one Farm Crest station that has 93 at the pump, but it's octane is boosted with alcohol and that attracts water. I add a bottle of STP ocassionally to to remove condensation build up. We have sharp temp. swings here. It's common to experience as much as a 50 degree differential in less than 24 hours, especially in late fall and winter.

 

[ridethelighteni]

Originally posted by LCCOBRA
:thumbsup: It's worth the extra loot...

Agreed. Only the best for my baby as well.

 

[kaboom]

Im in jersey 3 times a week they have 94 on 46 at sunoco.

 

[Quadcammer]

the brand of gas you run should have no affect on stalling. thats a computer error.

 

[D-Cobra]

i use Shell and BP, 93 octane of course. how do they compare to the Sunoco?

 

[woomaster]

A little information on gasoline. Gasoline companies only LEASE time on the gas pipelines. They do not drain the pipeline and pump in their own gas. Most gasoline you get is generic with the only difference being the additives that are used once it is put into the trucks. The differences there too are small.

 

[Narcosynthesis]

Woomaster is correct. I need to know about fuel for my job and the courses I've been through this topic is always brought up. Fuel is the same, it's the additaves that the company puts in that make it different.

Something like that anyway

 

[SMOKE]

CHEVRON/Mobil 93 only.

 

[a94cobra]

There is a fix for the stall. Not related the brand of gas at all.

And woomaster is correct. Your Marathon and Mobile might be coming out of the same pipeline.

 

[PhillyCobra]

Besides additive packages, there are differences in oxygenate content in various gasolines, which are location (EPA mandated) specific. For instance, some gasolines now have up to 10% ethanol in high smog areas, and they don't have to tell you about it. Other gasolines still use MBTE in some areas. The energy content of these oxygenates are different, so they can have an effect on performance. The mixture varies according to the time of the year, with vapor pressure being modified using various additives, which can also account for differences. through time.

 

[flyn high again]

Originally posted by a94cobra
There is a fix for the stall. Not related the brand of gas at all.

And woomaster is correct. Your Marathon and Mobile might be coming out of the same pipeline.

I've read many threads on the stall and fix. I just thought it was coincidental that my car would pick this time to start stalling. As I said, the only change I am aware of is the gasoline. I know one tank isn't enough for any kind of scientific testing but if it stalls with this tank and then doesn't when I go back to Mobil.... You guys can decide for yourselves what you think it means.

ps. Marathon gas is consistently 20 cents a gallon less than Mobil or other top brands so there are some differences in either additives or formulas.

 

[CobraKindaGuy]

Originally posted by kaboom
Sunoco 94 only over here.

Sunoco is 10% ethanol by weight if I am not mistaken.....not good for the longevity of these engines according to everything I have read.

BP Gas is the absolute worst gas in the world. Filled up my 97 Cobra.....I had to take it in to get the water out of the tank from the gas.

Went to a different BP and filled up the 96 V-6 Mustang....had to take it to the dealer to drain the tank becuase of water and sedimant in the gas.

Put it into my 03 Cobra and stalled out. Had to get a couple bottles of dry gas to dry out the tank.

Switched to Mobile 93 and have had absolutely no problems. Tried Shell V-Power and it bumped up my gas mileage almost 3 mpg. So Mobile or Shell are the reliable blends.