[RedBloodedAmerican]

Higher octane gasolines are no different than the low octane gasoline

They aren't? cool! Then we should be able to run the ATF on low-lead or even blue avgas! What a savings!

[Smartaleck]

Not only do the newer engines have octane sensors, they also have oxygen sensors and other electronic instruments to adjust the engine to the operating conditions.

Should someone start running a lower octane, which all modern cars can do, and experience hesitancy or rough idling.......one need only disconnect the battery for about 10 minutes. When the battery is re-connected and the car started, the computer will adjust the engine to the newer octane.

This tip comes from Ed Wallace the local Dallas car guru.
They guy knows virtually everything about the auto industry.
http://www.klif.com/host-wallace.html
Be sure to click on his personal web site.

[Proud_texan]

"3. High octane does not give you better gas mileage."

I've logged every purchase of gas for the 80k miles on my 12 year old car and can easily calculate the gas mileage.

On comparable road trips higher octane (89 is recommended) consistantly has given me better gas mileage than 89 so I figure the difference in price, calculate the 5 miles a gallon difference and buy depending on what will get me further for the lowest price.

Maybe it's just my car (a Toyota six banger). I also note I get a LOT of engine knock with 89.

[KansasConservative1]

From experience. My car gets 10% lower gas milage with 87 (low grade in Kansas) than with 90 (mid grade). The cost is about 2% higher. 2% increase in price for 10% better milage. I must also add that when I tried premium, my milage went to crap. I am a cheap-A$$ and would not pay a nickle more for somthing if I did not have to. I have proven this over about 5 years with my car. Everytime I question it and go through a testing period, I find the same results again. This is no myth!