I have recently purchased a 90'GXE, and am curious to hear what everyone thinks is the best grade of fuel. The previous owner stated that she always used 91 octane. Is this the best for my engine? Any suggestions would be appreciated. Thanks.

 

Take a look at your owner's manual for the correct grade. As a new owner, you should be reviewing it anyway.

 

down here in colorado you can get 116 octane it is pink and its 7 dollars a gallon that is the best to use but very expensive.

 

Waste of money to use an octane that high. And depending on if it uses lead to increase octane, it will foul the cat quite nicely.

 

Jeff, I did indeed look at my owners manual, but the manual is vauge and inaccurate in my opinion. I am sure 87 octane was fine for the engine when the car was new, but is it still ok for a 13 year old vehicle. I am just asking from everyones experience what is the best octane rating to put into my GXE since both models had the same engine that year(I think). After 13 years now, I am sure that alot of experience with different ocatane ratings have been put to the test and am simply looking for what most people have experienced as the best choice.

 

The only reason the engine "might" need a higher octane is if the combustion chambers have carbon. That will not only increase the compression ratio but the carbon will act as a match when hot and cause detonation. I would try a tank of 91. If it works well, you might try a tank of 87. If it doesn't work well, try 92-93(if you can get it).

Alternatively, you can get the carbon(if you have any) cleaned out of the intake manifold and combustion chambers by various diy and shop services.

It's quite impossible to really say what's best for YOUR car as every car is unique.

 

I gotta move to Colorado and get the "pink" stuff that's 116!!! I need 116!!. Oh wait DUH AV gas. Just 5 miles from my house.

 

i put a gallon of it in my tank when my car ran out of gas and it makes it smell weird, its reminds me of when i used to race motocross and thats all i used.