Bad Gas?????

**Dolce** · 02-14-10, 09:26 PM

I have been experiencing a little sluggish acceleration in the past few months. My car just doesn't seem to have that pin you back in the seat acceleration that it did during the summer. I know that the fuels are different in the winter and actually run a little less efficiently. I have had the same tank of gas since early November. I am finally getting down to the end of this gas and was wondering if there is an additive that someone would recommend that would help this if added to the next fill up. I have been using Sunoco Ultra and never had issue. The car does still pin you back in the seat but I do see a difference.
I understand Chevron is a good gas due to a certain additive; however, I do not have one in the area to check it out.
If this is bad gas, is there anything else that needs to be done.
Thanks,
Mike

**ProfessorBlaze** · 02-15-10, 04:28 AM

fill it up at the local shell cause a full tank of vpower is never bad.

before filling up with these here, add a can of b-12 chem tool. AWSOME stuff to clean your fuel system. not avai? use sea-foam in the fuel tank.
I will fill up at the 76 if no chevron or shell gas is around. BP is good gas if you have those as well.

**89blackvette** · 02-15-10, 07:58 AM

I had some bad gas a couple of months ago. Car would stumble on light acceleration once in a while and mileage went down from 24/25 to 19/20. Discovered that almost all gas in my area has 10% ethanol. I found one Chevron station that did not have Ethanol sticker on the pump. I put a can of sea-foam in and filled up there. Over the next couple of days stumble went away and mileage went back to normal. I only get gas at this station now as it is on my way to work.

**Hib Halverson** · 02-15-10, 09:02 AM

Gasoline with ethanol in it is not inherantly "bad gas" but it is a fact of life in most parts of the country.

Because ethanol-blended gasoline needs an air-fuel ratio just slightly more rich, your gas mileage goes down when you use it.

As for the original post...about using gasoline in the tank since November, simply go to the gas station and fill the car up with fresh fuel and some of your problem may go away.

From an additive standpoint, all major brands...Chevron, Sunoco, BP, Mobil and etc., for a given octane rating, will be virtually the same in performance.

**LLC5** · 02-15-10, 12:14 PM

Fuel that sits for months will go bad without a quality stabilizer added to it. There is nothing you can do to your old fuel to bring it back, but adding Techron Super Concentrate (20 oz bottles) to one or two "full to empty" tanks of fuel will help if there is any contamination present. Using Top Tier fuel is a good idea, you can google it to find their suppliers.

**gmjunkie** · 02-15-10, 03:24 PM

Originally Posted by LLC5

Fuel that sits for months will go bad without a quality stabilizer added to it. There is nothing you can do to your old fuel to bring it back, but adding Techron Super Concentrate (20 oz bottles) to one or two "full to empty" tanks of fuel will help if there is any contamination present. Using Top Tier fuel is a good idea, you can google it to find their suppliers.

**Hib Halverson** · 02-15-10, 05:41 PM

Originally Posted by LLC5

Fuel that sits for months will go bad without a quality stabilizer added to it. There is nothing you can do to your old fuel to bring it back, but adding Techron Super Concentrate (20 oz bottles) to one or two "full to empty" tanks of fuel will help if there is any contamination present. Using Top Tier fuel is a good idea, you can google it to find their suppliers.

I'm sorry, but the above is a bit nondescript. When you say "months" are we talking about 2 months or 12 months?

Fact is that gasoline is designed for a "cradle-to-grave" life of 6-8 weeks, however, gasoline can be stored for up to a year without degrading such that it will affect engine operation if the storage is in a dark place at reasonable temperature.

After 10-12 months, then fuel stabilizer should be considered.

Techron, which is a detergent-based fuel system and injector cleaners is a great product and is idea for light to moderate cases of fouled injectors or dirty fuel systems.

Top Tier gas is a good idea, but not required. In fact, if you regularly use Techron, you can run "third tier" gas and not have problems.

For more information on gasoline see an feature article here on the CAC at: Corvette Action Center Deep Dive Series: Gasoline for your Corvette

**Dolce** · 02-15-10, 07:25 PM

Originally Posted by Dolce

I have been experiencing a little sluggish acceleration in the past few months. My car just doesn't seem to have that pin you back in the seat acceleration that it did during the summer. I know that the fuels are different in the winter and actually run a little less efficiently. I have had the same tank of gas since early November. I am finally getting down to the end of this gas and was wondering if there is an additive that someone would recommend that would help this if added to the next fill up. I have been using Sunoco Ultra and never had issue. The car does still pin you back in the seat but I do see a difference.
I understand Chevron is a good gas due to a certain additive; however, I do not have one in the area to check it out.
If this is bad gas, is there anything else that needs to be done.
Thanks,
Mike

Thanks Guys, I will add the addative and fill up once we get out from all this snow. We had a Chevron station a few blocks away, however, they closed a few years back and now I cannot find one within 50 miles of my home. I will check out the Shell or BP gas.
thanks again,
Mike

**Dolce** · 02-20-10, 12:52 PM

Just found a site called pure-gas.org
This site indentifies any stations in your state with ethanol free gas.
I figure I will give this a try along with fuel additive and see what happens.
Wont be until this snow is off the ground. I live in Kennett Square, PA and there are three stations listed with Ethanol free gas in the state. One is within 40 minutes of my house in Gap, PA., which is a pretty good Sunday afternoon cruise route. Long way to go for gas, however, do you really need a reason to take a nice cruise in the vette?
One morning in October I was looking to take out the vette and asked my wife if she wanted to go to breakfast. She said yes, and asked where are we going.
I told her Uncle Bills in Ocean City, New Jersey which is a 100 miles from my home.
Take care,
Mike

**c4c5specialist** · 02-21-10, 11:41 AM

Hi there,
The truth of fuel injectors contamination vs fuel system cleaners and top tier fuels is very hard to determine.

Actually, top tier fuels benefits over a CUMULATIVE effect, NOT AN INSTANT effect.

Techron Plus is recommended by GM as a once per 3000 miles IF its not used.

I can give example by example case of injectors with flow rates that are better when using top tier fuels CONSISTANTLY vs not.

Techron plus was engineered as a cleaner when top tier is not used and DOES NOT create a better flowing injector when used once every 3000 miles as is recommended.

A higher detergency fuel like a TOPTIER rated fuel is a better course of action than just using the Techron.

Flow bench rates of 1.1 to 3.8 unit flow per second variation can be seen when NOT using Toptier fuels.

Allthebest, c4c5

**Dolce** · 02-21-10, 05:35 PM

Originally Posted by c4c5specialist

Hi there,
The truth of fuel injectors contamination vs fuel system cleaners and top tier fuels is very hard to determine.

Actually, top tier fuels benefits over a CUMULATIVE effect, NOT AN INSTANT effect.

Techron Plus is recommended by GM as a once per 3000 miles IF its not used.

I can give example by example case of injectors with flow rates that are better when using top tier fuels CONSISTANTLY vs not.

Techron plus was engineered as a cleaner when top tier is not used and DOES NOT create a better flowing injector when used once every 3000 miles as is recommended.

A higher detergency fuel like a TOPTIER rated fuel is a better course of action than just using the Techron.

Flow bench rates of 1.1 to 3.8 unit flow per second variation can be seen when NOT using Toptier fuels.

Allthebest, c4c5

Thank you for the information. I noticed a little slugishness and assumed it was the fuel. I always use Sunoco Ultra 93 octane. I just want to try the Techron with my next tank of gas just to help any ill affects of the last tank.
I am trying to figure out the best gas to use, I have read where alot of people are using Chevron, however, none to be found within 50 miles of my house. Some have mentioned Shell with V power, BP with Invigorate and of course Sunoco Ultra.
What are your thoughts about these brands?
I will use the best fuel possible every fill up. I have no intention of using anything but a TOPTIER fuel. This is the first I have heard about toptier fuel.
Actually, I just went to Toptiergas.com and of the names I listed above, only Shell is listed on this site for meeting the requirements of Top Tier gas.
I did locate a Shell station which is ethonal free.
Will I see a increase in performance using this gas?
Also, what is the highest octane rating that can be used? I believe the owners manual reccomends 91 octane or better.
Any reccomendations on what you have seen to be the best gas for the LS2 engine???
thanks again,
Mike

**c4c5specialist** · 02-22-10, 06:50 AM

HI there,

Using Toptier fuels is simply maintenance for your fuel system and combustion chamber.

91 octane or better.

After that, any fuel manufacturer can promote better performance, but truthfully, detergency is the only part of fuels that can be measured other than ethanol content.

Performance of a clean engine vs a dirty one can definately be perceived.

Allthebest, c4c5

**NORTY** · 02-22-10, 11:36 AM

Originally Posted by c4c5specialist

HI there,

Using Toptier fuels is simply maintenance for your fuel system and combustion chamber.

91 octane or better.

After that, any fuel manufacturer can promote better performance, but truthfully, detergency is the only part of fuels that can be measured other than ethanol content.

Performance of a clean engine vs a dirty one can definately be perceived.

Allthebest, c4c5

c4c5, you are correct about using "toptier" quality fuels and oils.

Some of the fuel marketers create ambiguous names for their products. This is to give the buying public the "perceived increase in quality" of their fuels, as compared to other marketers. Usually, these "added products" do add detergency to the fuel. **This is going to play a larger part in drivability/customer satisfaction in the near future.*** ( With DI powerplants.)

Since the criteria for selling gasoline in the USA is so tightly regulated, there are very few variations (formula wise) that comply with Gov't regulations.
The Gov't does not formulate fuels. They only create regulations, and let private industry come up with formulas to comply with those regs.

There are numerous things that can be measured reguarding gasoline. Vapor pressure, acidity, water shedding/absorption, additives, API gravity, corrosion inhibitors, octane, BTU value, many more but I'm having a "brain fade" moment!

Gasoline's detergency is supposed to minimize intake valve deposits. This will become key with the advent of DI engines now.

**c4c5specialist** · 02-27-10, 06:39 AM

I should have said that detergency and ethanol content are the parts that can be measured BY A TECHNICIAN, in a shop.

Allthebest, c4c5

**killain** · 02-27-10, 07:40 AM

I live about 25 miles from you, In Essington, PA and about the only gasoline around here in SE Pennsylvania is Sunoco. The GM master technican who does my maintenance work on my 2003 LS1 has always cautioned me against using Sunoco as he says it has too much sulfur content? I 'don't know, but I do know that when I put my Vette away for the snow season (and it's been a long one) my car runs a little poorly when i first take it out.

But as Hib has said, Gasoline really doesn't go bad in the course of one winter. after the snows gone, I take it out on a nice Sunday and run it till it's close to empty, refill with either ExxonMobil 93 or Sunoco 94 and any roughness usually disappears. Although I also put a bottle of 'Techron' in once a year. Here in PA, we don't have much of a selection when it comes to gasoline.