Flex Fuel or No Flex Fuel. That is the question.

Who has a flex fuel Tundra? Do you use flex fuel? Or Unleaded/Premium?

 

I have flex. All we can get in CO per the dealer when I bought it. Could have been BS but didn't have another choice at the time since it was taking weeks to get white ones in. I've never used flex fuel so I have no info about it.

 

I've been using flex fuel. Gas station down the street from my house has it. Some friends said don't use it. Use Premium. Flex fuel is cheap and not worth the loss in mpg.

 

I don't use premium because it's not a performance engine, so doesn't need higher octane. So I use regular. I could be wrong, and if I am I'll hear soon enough

 

If I had a choice...non flex-fuel

 

And that's why I posted this here. LOL.

 

non flex here and If I had a flex fuel engine I wouldn't use flex fuel at the gas station

 

I have a flex fuel but I never use flex fuel. I do use premium only because Im heavy on my gas pedal and I like to run the higher octane. In my area you can't find a non flex fuel Tundra. At least not to my knowledge.
The Toyota mechanics I talked to at my local shop said, don't use the ethonal fuel unless you want to service your truck twice as often. They said the ethonal doesn't lubricate the motor as well as typical gasoline and it causes more carbon build up. I do not know if this is correct but I do wonder.

 

Good ol' gasser (non flex). Wouldn't want flex... I kinda like the idea of a supercharger, even if it doesn't happen. haha

 

I wanted non-flex but Texas only sells Flex, I will never use Flex fuel, always use Premium! Thats just me! Like most people use the cheapest unleaded because of price, I always use the premium in all my vehicle, just a peace of mind for me!

 

flex vs non=flex engines are basically the same engine but a few tweaks in the flex engine, just use non flex fuel in a flex engine and you have a non-flex engine!

Just look at it like a non-flex is like a cheap whore and flex is like a cheap whore but a little bit tighter!

 

Mine is flex fuel, but I've never used it. I just run regular.

 

non flex-reg. 87 up north, no issues!

 

I do NOT care Flex Engine or Non-Flex Engine. To me the Flex engine is based on the non-flex engine with additional parts/items/tunes. If you don't EVER use E85 then the Flex Engine is a "better - as more complicated/more expensive" engine because in the gas-armagarden situation where there is ONLY E85 available then your Flex engine is golden...

I have NEVER used E85 and don't plan to but I have done my unscientific test on E10 89 vs. pure 87 ($.05 more expensive) and my Tundra likes pure 87 better. I got more miles per tank and my mpg is better as well. Also, I don't feel "jumpy" at initial stab of the gas pedal on 87.

 

Maybe I'm wrong here, but isn't the meaning of the octane reading meant to indicate how quickly gasoline gases will expand in a space? So 91 octane gasoline's vapors will fill up the cylinders faster than 85 octane. High performance engines need 91 or better since they run at higher RPMs and lower octane can cause engine knock. So 85 vs 91 is more about gas expansion vs quality. Is my understanding incorrect?

 

My previous truck wasn't a Tundra, but it was designed for E85. There is a definite advantage to running an occasional tank of E-85. It cleans the injectors beautifully. My S-10 (I had this before my Tundra) sat for over a year before I bought it. The injectors had probably varnished a little and a tank of E-85 cleaned them right up. On the down side, some vehicles turn off many of the IM readiness sensors and will not reset them if you're running more than 10%-15% ethanol. The EPA published a document on E-85 testability issues, but it's disappeared from their web site. For a while I ran mostly E-85 for a while due to the price (I was paying as low at 75 cents a gallon after the grocery store discount), my figures show it's somewhere between a bit of an advantage and a break even at full price, and saves a little with the discounts. I had to switch to straight E-10 (that's the best that's available around here) to get it to pass state inspection, and only then after some expensive repairs. I had to change batteries and lost the settings and no one could figure out why the monitors wouldn't reset. After a new computer was installed and the tank refilled (with E-10) and a lot of driving, it finally reset enough to pass. I found out what was causing the problems much later. When I ran through the GM drive cycle, very little changed on E-85. http://www.obdii.com/drivecycle.html Few, if any, of the inspection stations around here know about E85 issues, and even fewer mechanics know the possible problems. The EPA document hasn't been updated for modern vehicles, so I don't know if any of the new Toyota's are affected. I wouldn't risk it.

 

The 85 means it's 85% ethanol (most is 10% these days), not that it's 85 octane. If you put E-85 in an engine that isn't designed to run it, you can do some serious damage.

 

Yep, I didn't mean E85, just regular 85 Octane. Sorry I wasn't more clear on that when I posted.

 

E-85 is 85% ethanol. The octane rating is actually much higher than gasoline which is why it is great is boost applications. Higher octane fuel is less prone to detonation. In states like Colorado, lower octane is acceptable because there is less oxygen content in the air so the chances of detonation are much lower to begin with.

Colorado Octane choices at 7-11 85/87/91 (higher altitude)
Kansas Octane choices at QT 87/89/91 (lower altitude)

If you can avoid it, don't buy a FFV Tundra. More parts = more problems. This is especially true if fuel is bought from multiple sources and the tank is not filled every time. There are several issues with the fuel/alcohol content calculations, especially if the tank is not filled all the way every time fuel is added.

 

Ok so I guess I'm not going to use the flex fuel anymore. Do I need to use the premium or is regular unleaded fine? I want what is best for my truck and to get the best mileage I can.

 

I use regular. Costco only has 85 or 91. So 85 is my drink of choice

 

Yeah now I need to use my Gas Buddy to find the best price. What is COSTCOs going price on Reg?

 

Last week I believe was $1.89 . . . don't quote me. I would have to check the receipt.

 

Does anyone know how to do a throttle body reset? Do you think that needs to be done with the new CAI I have on it? Might help my truck get better mileage to relearn the system.

 

Yeah need to go by there and fill up next time.

 

Clean the throttle body, then disconnect the battery for 10 minutes.

 

What do yo mean by clean the throttle body?

 

And I only have 3k miles on this truck.

 

Well, with a throttle body cleaner. If you only have 3k miles though, I would just disconnect the battery for 10 minutes. Keep in mind, the first time you start it back up, it will probably die. This isn't a concern. Just start it back up.