I have a 2007 GMC Yukon With the 5.3 Flex Fuel and I have run E-85 in it a few times in the past. In the last month I have been filling up with it every time. Basics are the fuel prices especally duing and right after the hurricane in Texas, but also it seems to give my truck more power and it runs better on it. My main question is do I need to be adding an additive to the fuel system on fill ups or every so often? I am sure that thier is some draw back to the ethanol I know that it will eat rubber lines etc. I run royal purpule oil and stock fuel system filter etc. any advice or experince will be greatly appreciated.
Thanks
SAS
I, too, have a 2007 GMC Yukon - took delivery on it in March 2006. I have been running it on E-85 almost exclusively since we bought it. Only times it has had gas in it is on long trips when E-85 isn't available. More and more stations in my area (southeast AZ) are selling E-85, and they get my business. I intend to run nothing but E-85 in my Yukon whenever possible. Perceived preformance and responsiveness is slightly better when burning E-85.
As others have said, your flex fuel engine is set up for E-85 - you will have no problems running E-85, or gas, or a mixture. Note that GM did initiate a campaign to re-flash your ECM to better read the mixture ratio of gas and E-85 when you run a combination. If you haven't taken your Yukon in for that, you should.
The National Ethanol Vehicle Coalition has an informative web site (
www.e85fuel.com) that discusses all aspects of E-85 - production, octane, power, carbon footprint, etc. Good comparison to gasoline, some good FAQs. It makes for a good read.
I did some back of the envelope calculations to determine how many equivalent barrels of oil I would burn in a year using gasoline, and then made the same calculations for using E-85 assuming a 24% reduction in mpg. To the best of my memory, it turns out using gasoline for a year I'd burn about 40 barrels of oil; with E85 it drops to about 8 barrels. Or another way to look at it - burning E-85 my "effective gasoline MPG" is about 70 mpg. This is because, using E-85, every tankful of fuel is only 15% gasoline. So your 26 gallon tank of E-85 contains 3.9 gallons of gasoline. In my town, E-85 is NOT 24% cheaper than gasoline, so if I wanted to save money, I would be better off burning gasoline. I have chosen to reduce my usage of foreign oil and give my money to American farmers.