Hutch

I have a 2006 Sub, 5.3L Flex Fuel, was getting 24 mpg hwy 18 city and tried the E85, mpg dropped to 16 mpg hwy and 11 city.
After running 5 tanks of 87 octane fuel my mpg only went to 21 mpg hwy and 15 mpg city.
Unfortunantly another fillup of E85 was ran in the Sub, now the mileage dropped to 13 mpg hwy and 9 mpg city.
I replaced the plugs, cleaned the injectors and ran 10 tanks of 87 Octane.
The mileage is 15 mpg hwy and 11mpg now...
The E85 should be Banned For Ever...
The dealer reset the computer and still no change.......
Anyone have ideas

ousig2408

E85 is a complete joke, as you now know mileage suffers so much it is not even close to being worth it $$$ wise. are you basing your fuel mileage #s off of the computer readout or by hand calculating? I find it hard to believe your Burb was really getting that MPG before you tried E85 - if so you were very lucky

Hutch

I had a 2005 Sub 4x4 1500 that got 23.8 mpg from Sacramento to L.A. and the 2006 Sub 4x4 1500 was getting 24.2 mpg.
I also have a 2002 Sliverado with 300k miles and gets 21 mpg.

It's no trick....Just don't lead foot it, and the Sub's like the hwy speed of 55 to 62 mph, As for the truck I get the 21 mpg doing the commute traffic hwy and city.

ousig2408

ok yes if you go 55mph on the highway then I would imagine you could see that mpg, but I would rather not get ran over going that speed...I keep our Tahoe at 70mph and see 19.5 - 21 regularly hand calculated.

JimJ

What brand of gas are you using? Is it a top tier brand?

JRacer

MPG is the wrong measure to use when comparing gasoline or mildly diluted gasoline with E85. I have been calculating cost per mile in order to get an apples to apples comparison. This measure accounts for the difference in price between the fuels and also accounts for the difference in "bang" between gas and alcohol. In the 8500 miles I have put on my 2010 Flex Fuel Suburban, I have found that gasoline is cheaper on a cost per mile basis to run than the E85. Obviously, it depends on the magnitude of the difference in the price per gallonand I have seen from 10 to 30 cents a gallon difference. Based on my experience, I believe that the selers of the two fuels know that about a 20-25 cent per gallon "savings" on the [purcvhase of a gallon of E85 is about what it takes for the E85 to equate to a gallon of gas in terms of cents per mile of fuel.

I've switched back to gasoline.

Hutch

Figuring out MPG is not rocket science
I did go to the dealer and had the ECM re-flashed, lucky for me there's a service recall on flex fuel problems if your milage is not over 80k miles.
Just made it .....79k

After the reflash, I am back to 23 mpg.....yesssssssssss
No more E85.............

kdbb_1

Never had any problems great 159,000 miles until one tank of flex fuel and the Tahoe shut down on highway and needs new fuel pump and all lines cleaned out.... never again with the lost gas milage and the thousand dollars for the new pump!!!! what a joke!!!

SabrToothSqrl

Is the 04 flex fuel compatible? I can't blame E85 or GM if your car isn't... sorry... even many new 2012s aren't E85 compatible... and several companies will not warranty ethanol damage. one of my EXs actually put about a gallon of Diesel in her Saturn before realizing the mistake... local place has both on same pump (2 handles).

I know, let's use a major FOOD source and make it a FUEL.

Cows eat corn, I eat corn, I eat cows.

I don't eat oil!

E85 has raised the price of FOOD, causes more pollution than burning gas, ruins engines, costs more to use than gas (Miles Per $1.00). and was only ever used to get votes.

Someone promised some farmers more $ for their corn to get elected.... tada E85... which is fine for people who make over $250,000 a year and just buy a new car every 3 years. speaking of, I'll put a thread up on that, because after some number crunching, it may be CHEAPER than a 10 year replacement cycle...


and yes, if you run the MPG vs cost, E85 still doesn't work, even though at the pump your tax $ help make it cheaper!

$4.00/ gallon gets me 17 MPG E10 (because no where in PA near me has real gas)
or $3.00/gallon for 12 MPG....

4/17 = $0.24/mile E10
3/12 = $0.25 mile E85

IT DOESN'T WORK. For your pocket, for the economy, or for the environment.

in2pro

kdbb_1 Welcome to the forum...
sorry to hear of your dilemma... I have to agree with STS, is the 04 Flex fuel compatible ? It may have been offered but the engine has to be designed for it... do you have the FF sticker? is it listed in your RPO codes, i think its L59 or LMG...