Colorado Octane

Old school mechanics always say "if you have carburetored vehicles at high elevations, you fill up with lower octane gasoline." My wifes '00 Jeep Wrangler ran like crap since she was following her fathers advise of high elevation lower octane and filling up with 85 all the time (he worked in the Pentagon for 30+ years and 'knows all'..). We live at 7000'. It ran rough, started hard.
Reading the Jeeps owners manual, it states 87. I filled up the tank, at empty, and within 7 days it was running as a different vehicle. Started right off, no more stumbling, and the mpgs came up. And my wife even noticed.
I have been living at 7000' since 1992 with 4 and 5 cylinder 1980s VWs and Audis, never seen any improvement with higher than recommended octane gasoline.
With the Tacoma, in 13xxx miles I have yet to feel a difference with higher than 87, which is what the owners manual states.

 

Have you tried running 85 in your Tacoma?

 

I used to live in CO (pushed out due to the ridiculous housing market there) anyways I started with 85 then quickly switched to 87 after reading countless articles about how it can affect your engine.. figure it is cheaper to spend $2 more per fill up than to have engine service repairs.

Everything I read made it seem like 85 was ok for the old carborated engines. Newer fuel injections are more sensitive but I'm not a mechanic.

 

No, and never thought about it.

 

I'm at 5k ft, so bit lower than you. Although I frequently go over passes 8-9k (yeah, I know you guys have much higher passes there!). No issues whatsoever with 85 octane. FWIW.

 

Same and I live here...

 

It's 86 in New Mexico. Never a problem.

 

If I ran 85 in my '98 it ran like shit, especially up over the passes here. I noticed a huge difference running higher octane fuel through it.

I know we're talking 3rd gen here, but due to my experiences with my '98 and different octanes I only run either 87 or 91 in my 2016.

 

87 all the time in my 3rd gen

 

Don't even worry about the drive back. I had a full tank of 85 when I left Estes Park ... and was filling up again before I was down enough in elevation.

The "downhill" through Kansas is so long and gradual you won't even notice. Be careful with those overpasses if you take rt 70, sudden loss of the Kansas cross wind can be pretty scary if you aren't expecting it. Now there's something to worry about.

 

I doubt it matters much on the gradual downhill. My drive consisted of dropping from 6800ft in CO down to 2400ft in KS before I filled up again. Probably just me being cautious with a brand new truck. First new truck in 19 years and less than 1k miles on it when I went to CO. Used 85 in my old Trailblazer when I was there before and never even noticed a difference.

 

Interesting. My '98 ran fine on 85 the entire 9 years and 210K miles I owned it. Same for my 2004 4Runner over 12 years and 250K. I've never run anything but 85 in my vehicles in the 20 years I've lived in CO. A few months ago I stumbled upon a station near my job that sells E-free 87, so out of curiosity I tried it thinking I should see a little better mileage. Nope, no difference in mileage or performance between the two after 3 consecutive fill ups (about 1000 miles). I went back to 85 after that.

 

Mirrors my 20+ years of car ownership in Colorado as well.