Here in Missouri and most other states I've visited, the grades of gas are usually 87 Reg, 89 Mid and 91 Prem. Of course, I've seen up to 93.

I went to Colorado for vacation and saw constantly 85 or 86 Reg. I have never seen it that low, is this a high elevation thing? I was really hesitant to use 85 and paid extra to use Mid to get up to 87 to match what I always use back home. First time we've been to Colorado but for some of those mountains we had to climb, I would of thought one would want higher octane....

Is it okay to use this low octane fuel in our trucks if I come across it again?

 

If u have a flex fuel truck, then u can use 85. I wouldn't recommend it, but the engine is set up to use it and be fine. I wouldn't use anything less than 87, especially if u have an ecoboost engine.

 

I did the same thing on a recent trip through there and east of there....if the owner's manual says to use 87, then that is what I am going to use....don't trust any octane less than that!
It was disappointing at times to see gas advertised at a really good price, pull up to the pumps, and realize that the posted price was that cruddy 85 gas!

 

i've always wondered that man.

i've got the flexfuel emblem on my truck, but i've never come across it.

would i lose mpg if i used it?

 

To answer your question Yes it is a high altitude thing. I grew up in Denver. Because the air is less dense they are able to get away with lower octane ratings If you have an eco I agree use the mid grade !

 

It's not common to come across, at least not in my area. I've seen it at a couple of stations while taking a road trip to Nevada. Never tried it myself but from what I've been told, it's cheaper than regular gas but it lowers mpg, so u have to fill up faster. So I guess in reality, it actually comes out to the same price, if not more than 87 octane

 

FYI the 85 octane sold in Denver is not E85.

E85 is a diff fuel all together

 

i'm up in canada, and haven't come across it. lol.

altho, i've seen 94 oct at the pumps, and i gotta admit, i ran it sometimes in my 2002 dakota, but won't in my ford, unless it's all i got offered while holding a gas can lol.

but, for the flex trucks, since the lower oct gets less mpg, then... couldn't someone claim that a truck with flexfuel will always come with the bigger tank, so if it does in fact run on 85 oct, then it could go just as far as a truck on 87oct with the 26gallon tank, vs my flex36gallon?

 

Just to make sure we are on the same page! Just because the octane is lower it does not mean the power of the fuel is any less. As a matter of fact a lower octane rating fuel burns faster producing more "energy per fuel used" Octane is ONLY the rating at what point the fuel begins to pre ignite in the cylinder.

http://en.wikipedia.org/wiki/Octane_rating

A 93 octane fuel that has %15 ethanol blend will give you worse MPG then 93 pure gas

And in some cases a 93 fuel with 15% ethanol will give you worse MPG and power then an 85 pure fuel. It depends on the motor!

Flex fuel regards Ethanol IE E85

 

Whoops! I automatically assumed the OP was talking about E86 since I've never came across regular 85 octane fuel. Disregard what I said, as it does not apply to the fuel ur talking about