Absolutely incorrect with fuels now days. When these truck were originally designed ethanol was not being added to fuel. They were never designed for the added combustion temps which lead to detenation. Also 91/93 has more anti knock agents added, which allows more timing and better effiecency.

Custom programs are the ticket.

 

When these trucks were originally designed??? Ethanol has been in the mix for almost 4 years now over here. I'm pretty sure theses engines are designed to allow for the ethanol. Anyway, it says 87 recommended, and it does not say to change this if ethanol is in the gas. My 2 cents.

 

It may not say it, but you have to look at several other factors. I know for a fact that even when I my truck is not running a custom tune it runs better, smoother, and get better MPG on premium than on 87.

 

My stock 2000 gets the same mpg on premium that it does on 87 octane. However, I do run a tank of premium every now and then since premium had more engine cleaners in it.

 

Oh it runs exactly the same too.

 

See your talking about not having ethanol I'm talking about higher octane. You can still get 87 octane with no ethanol in many places so your argument is completely invalid. And how exactly will you change the timing to adjust for the higher octane? Oh ya a tuner. Which is what I said. So actually everything I said is absolutely correct. Oh and heres some sources if you still don't believe me.

http://answers.yahoo.com/question/in...1013230AAGO4a3
http://www.allfordmustangs.com/forum...ifference.html
http://ask.metafilter.com/79327/Is-i...nce-in-a-while