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RECENT EMAILS: Fuel Octane Ratings. High octane gas might help lower NOx. Remove carbon deposits. Knock, pinging or rattle. Regular 87, mid-grade 89, premium 92 gasoline.

Question:   I just purchased a 2005 Buick LeSabre with 3800 engine. i live in iowa and need to know what octane gas would be best for this vehicle.
 
Answer: High octane gas might help lower NOx if your vehicle suffers from this failure. High octane burns cooler and slower (keeping NOx low), but it also produces less power which your engine might not be ready for. This could cause other emissions such as HC and CO to increase. It is recommended to use ONLY the manufactures required octane at all times, specially during a smog test. Your vehicle's emissions computer is programmed to process information based on it's required fuel octane. The Low-Down on High Octane Gasoline:
 
Are you tempted to buy a high octane gasoline for your vehicle because you want to improve performance? If so, the recommended gasoline for most cars is regular octane (87). In most cases using a higher octane gasoline than your owner’s manual recommends offers no benefit. It won’t make your car perform better, go faster, get better mileage or run cleaner.

If your car engine knocks when you use the recommended fuel you might want to try filling a higher octane level. A small number of vehicle might experience engine knock using the recommend gas octane.
 
Buying higher octane gasoline when your engine is not knocking is a waste of money. Premium gas typically costs 15 to 20 cents more per gallon than regular. Studies show that vehicle owners may be spending hundreds of millions of dollars a year paying for higher octane gas than needed.
 
So what are octane ratings? Octane ratings are a measure a gasoline’s ability to combust; resist engine knock. Engine knock is a pinging or rattling noise that results from premature ignition of the fuel-air mixture in one or more engine cylinders. Gas stations offer three octane grades: regular (87 octane), mid-grade (89 octane - a mixture of 87 and 92/93, mixed at the gas station) and premium (usually 92 or 93). The ratings are posted on yellow stickers on each gasoline pump.
 
What octane should you choose for your car? Read your vehicle owner’s manual to determine the right octane level for your car. Most vehicles requires regular octane. However, some high performance cars with high compression engines, like sports cars and certain luxury cars, require mid-grade or premium gasoline to prevent knock.
 
You can tell if you're using the right octane level by listening to your car’s engine. If it is not knocking, pinging or rattling when you use the recommended octane, you’re using the right grade of gasoline.
 
Can using a higher octane gasoline clean your engine? High octane gasoline does not outperform regular octane in preventing engine deposits from forming, in removing them, or in cleaning your car’s engine, unless the gasoline has had carbon cleaning additives added to it. The U.S. Environmental Protection Agency (EPA) requires that all octane grades of all brands of gasoline contain engine cleaning detergent additives to protect against the build-up of harmful levels of engine deposits during the life of your car. Some gasoline manafacturers add more.
 
Should I switch to a higher octane gasoline? A few car, truck, van, SUV and RV engines may knock or ping when using the recommended octane rating. If this is happening to your vehicle, you can switching to the next octane grade up. Switching to the mid-grade or premium-grade gasoline will eliminate the knock in many cases. If the knocking or pinging continues after one or two fill-ups, this may be an indication that your vehicle needs a tune-up or other engine repair. After the repair/s is done, switch back to the lowest octane grade at which your engine operates without knocking.
 
Is engine knock harmful for my vehicle? Occasional a light knocking or pinging won’t hurt your engine, and does not indicate a need for higher octane. But we don't recommend ignoring severe knocking. A heavy or persistent knock can lead to engine damage, and may be an indication of a more severe engine fault.
 
Are "premium" or "regular" gasoline the same, even if they are from different gas stations? The octane rating of  "premium" or "regular" gasoline is not consistent across the country. One state may require a minimum octane rating of premium gasoline to be 92, while another state may allow 90 octane to be called premium. Make sure you know what you’re paying for by checking the octane rating on the yellow sticker on the gas pump instead of relying on the name "regular" or "premium".
 
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Question: I have a 97 nissan altima sit in garage for 5 month. When i start the car several days ago, it smell bad. So do i need to use up all old gas in the gas tank and fill in new gas before i go smog check?
 
Answer: We highly recommend you do that. Old gas will not burn as efficiently as fresh fuel. Go ahead and use up the old gas and fill fresh 3/4 tank before the smog check.
 
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Question: I was wondering if the octane level of the fuel has any bearing on the emmisions of the car. Also, if a fuel additive (fuel system/injector cleaner, Sta-Bil fuel stabilizer, etc) affects the emmisions (either positively or negatively) if it is present in the fuel when the test is administered.
 
Answer: High octane gas might help lower NOx if your vehicle suffers from this failure. High octane burns cooler and slower (keeping NOx low), but it also produces less power which your engine might not be ready for. This could cause other emissions such as HC and CO to increase. It is recommended to use ONLY the manufactures required octane at all times, specially during a smog test. Your vehicle's emissions computer is programmed to process information based on it's required fuel octane. The use of fuel additives can be very helpful in lowering emission levels. Fuel additives are generally poured into a vehicle's gas tank during fuel refilling and mixed with ordinary fuel. Their purpose is to clean carbon deposits with in your engine's intake and exhaust systems, allowing for both fuel and air to flow freely within its passages, thus lowering emission levels and improving overall engine performance. These products offer helpful solutions to various vehicle emission problems.

  
 

 

 

 

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