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I been driving Jeeps for awhile now, on my third one. First was a "81 CJ 7, then a "88 YJ, now I own a 4.0 "99 TJ. I wanted to know what octane of gas you all are using ? My owners manual says a rating of atleast 87, duh, but it also says " THE USE OF PREMIUM GASOLINE IS NOT RECOMMENDED. THE USE OF PREMIUM GASOLINE WILL PROVIDE NO BENIFIT OVER HIGH QUALITY REGULAR GASOLINES AND IN SOME CIRCUMSTANCES MAY RESULT IN POORER PERFORMANCE. Where I live in SouthEastern Illinois and where I work in SouthWestern Indiana, the " cheap " 87 grade of gas just smells funny each time I fuel up, and no I don't go around huffing gas, LOL. :D I like to run 90 octane. I just wanted to know what others use and there thoughts...
 

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Higher than recommended octane can actually leave more deposits as it burns slower than a lower octane does. In other words, it may not fully combust in an engine not designed for it. Higher octane fuel does NOT add power, the added octane's ONLY purpose is to help the gasoline prevent being ignited prematurely from compression. That is ALL that octane does. So if your engine isn't compressing the fuel enough that it is self-igniting (pinging) on its own, then paying more for high octane is a foolish thing to do. That the gasoline producers love you for doing though. ;)
 

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Running 87 in my 4.0 with no problems. Heck I even run that in the 5.3L V-8 in my Tahoe.
 

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Guess i had to be the different one. Depends on how tight money is that week on what i put in it. I have done a tank to tank comparison though and i get more miles out of the 93 octane then i do the 87. I run 87 alot but sometimes i will run super just to clean everything out. Keeps everything working smoothly. Some will disagree im sure but i can pull my intake off after burning through a tank of it and hardly any carbon build up at all in it. Do what works fer ya.
 

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higher octane levels of gas are made for use in older vehicles or modified race engines. Octane does not improve mpg at all it helps eliminate knocks that older vehicles have and make them run smoother. So if you don't mind spending extra $$$ for no benefit buy the high price stuff. If not stick to what your owner's manual says.
 

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Hi
Now i'm a bit confused. I've always used 93 because when I switched to 87 it started rattling/pinging really bad. I'd love to go back to 87 though.
 

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Yes there is a difference between 87 and 93 or what ever the higher number is at your station. The 93 contains cleaners in most cases that the 87 does not. Thus, if you start useing the 93 it may help to clean up a dirty system and you might see some slight gains in mpg, but it most likey means the system is now running how it should be. I know in my truck after about 5-8 fill ups of 87 it has hard start issues. I can do one of two things Dump a 5 dollar bottel of techron in or just use 93 vs 87 every couple of tank fulls.
 

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Thanks!!!
I guess I'll try 87 when i get my next brand new Wrangler.
 

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Mudweiser said:
I have done a tank to tank comparison though and i get more miles out of the 93 octane then i do the 87.
Those who fully understand what octane is and does know that running higher octane than the engine requires to prevent pinging or knock will not help improve fuel economy even .00001 mpg. Octane has NOTHING to do with fuel economy. Nada, zip. I can do a lot of things that will vary my Jeep's fuel economy but it mainly has to do with my foot. ;)

By the way, even Chevron at http://www.chevron.com/products/prodserv/fuels/bulletin/fuel_economy/ says "Don't Buy a Higher-octane Gasoline to Improve Fuel Economy". Now it has been proven that the QUALITY of a gasoline can affect/improve/decrease fuel economy but octane level itself has nothing to do with fuel economy.
 

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Jerry, I think that what some of them are saying is that if you are running a vehicle that the fuel system has been somewhat neglected and you run a higher octange fuel for a couple of tanks, it can in fact increase the effeciency of said vehicle by providing the cleaning agents that haven't been there.
 

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I guess I am unique. They do not have Octane 87 here. I run 86.5 usually. That's the "regular" gasoline level in Europe. My Jeep does ping sometimes, then I throw some higher octane in it to clean it up. Mid-grade is 90 and high is 93.
 

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1BLKJP said:
Jerry, I think that what some of them are saying is that if you are running a vehicle that the fuel system has been somewhat neglected and you run a higher octange fuel for a couple of tanks, it can in fact increase the effeciency of said vehicle by providing the cleaning agents that haven't been there.
But where they'd be wrong is on the false rumor that higher octane gasolines of today's major brand gasolines have more cleaning additives than, say, 87 octane does. 87 has the same amount of fuel injection cleaning additives as 91 octane does, at least as far as the major brands go. :)
 

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I also heard Chevron put more techron in the 92-3 octane.As stated the higher octane will do nothing for power in our Jeeps.
 

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I was running 87 when I bought the Jeep, It pinged like CRAZY!
Since then I fill up with 91 and the i6 no loger pings! But every vehicle is different!

-John
 

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I was running 87 when I bought the Jeep, It pinged like CRAZY!
Since then I fill up with 91 and the i6 no loger pings! But every vehicle is different!

-John
If it is pinging with 87 it's because you have carbon build up in the cylinder head, this carbon gets hot and glows which in turn causes the gas to ignite early, when you run higher octane it has inhibitors that make it harder for that carbon or the spark plugs to ignite the mix. What you need to do is get the carbon out of the combustion chamber. There are several ways to do this, Chevron Techron FUEL SYSTEM CLEANER [Not fuel injection cleaner], Sea Foam poured thru the throttle body and left to soak or if you have the knack you can use water dribbled into the running throttle body. The water does a really good job, the engine turns it to steam which penetrates the carbon and expands within the carbon blowing the carbon out big time. What you have to be careful of is too much water which can warp the head pretty dam quick. That I know from personal experience on my moms 66 6 cylinder Mustang way back in 68, I warped the head, I sneezed while pouring :banghead:
 

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higher octane levels of gas are made for use in older vehicles or modified race engines. Octane does not improve mpg at all it helps eliminate knocks that older vehicles have and make them run smoother. So if you don't mind spending extra $$$ for no benefit buy the high price stuff. If not stick to what your owner's manual says.
Higher octane DOES improve fuel economy. The higher the octane, the slower AND cleaner the burn. The slower the burn=less fuel consumption. The cleaner the burn=better and longer engine performance.

I only run 93 octane in ANY Jeep I'll ever own. I find that the higher octane keeps the carbs running a bit better as well.
 

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Higher octane DOES improve fuel economy. The higher the octane, the slower AND cleaner the burn.
I hate to be so blunt and I seldom am this blunt but that is complete baloney. More octane than the engine is designed for does not improve fuel economy, and higher octane fuel certainly does not burn cleaner or leave fewer deposits behind in an engine designed to run with a lower octane. :)
 
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