5.3 Mileage

svaneld · January 18, 2011

Has anyone seen a difference in their mileage when they use fuel from stations with "up to 10% ethanol" vs ethanol free fuel? I have a 2005 Sierra 5.3 and it is not the flex fuel engine. Was the flex fuel offered in 2005? Either way I was watching and I was getting 10.7-11 mpg's with the 10% ethanol and decided to try ethanol free and my average mileage now is right around 13 mpg. By the way I am nearly 100% in town driving right now. Is that a normal gain to have when I dont get the ethanol stuff? I also found a place where the ethanol free fuel is same price as the other stuff.

bartonjude · January 18, 2011

Yep, my fuel dipped 1 to 1.5 MPG with the 90/10 blend.

Stevens03 · January 18, 2011

Yep, between 1-2mpg difference both with my 5.3 then my 6.0 when using the 10% verses none.

I can't even find a local station that doesn't have 10% ethonal in it anymore.

frupp · January 18, 2011

My 2004 Suburban has the 5.3 flex-fuel engine. With 10% premium ethanol gas I get about 18 MPG on the highway, the best ever was 18.5. We have a gas station here that sells premium 93 octane ethanol-free fuel. I use it in my boat and when use it in my Suburban for long trips my mileage goes up to 21 mpg.

stlavsa · January 18, 2011

Yep, between 1-2mpg difference both with my 5.3 then my 6.0 when using the 10% verses none.

I can't even find a local station that doesn't have 10% ethonal in it anymore.

I dont think i have ever seen on in my lifetime

Eddie 70 · January 18, 2011

Try looking here for Ethanol Free Gas. You might have a station close to you.

http://pure-gas.org/

Mckenzie · January 19, 2011

good website +1, we run ethanol free gas in our outboard motor, and that was the website the guy at the marina told us about.

MikeNH · January 19, 2011

Only one in my state is in a town named Freedom. Go figure.

JRLZ71 · January 19, 2011

Just read that a lot of stations will be going up to 15% ethanol. That's nuts!

MikeNH · January 19, 2011

Just read that a lot of stations will be going up to 15% ethanol. That's nuts!

It was proposed but it may or may not happen. And last I looked it was to be a standalone option like E85 because not all cars can run it.

cghbuilder86 · January 19, 2011

I see about 1-1.5 mpg better when using ethanol free. Not a lot but it does cover the difference of 10 cents more per gallon. Plus I like to see the higher number and see my gas gauge move a tiny bit slower.

Most all station now days are going to be 10% ethanol unless it says ETHANOL FREE. There is one near where I live. The ethanol free is always exactly 10 cents more per gallon, but well worth it.

svaneld · January 19, 2011

Thanks for the reply's all. I feel for you guys that dont have the option of ethanol free. I am lucky, I have a station less than a mile from my house and their prices are same as the other stations. I would gladly pay the extra $.10 per gallon for the ethanol free if it makes this kind of difference.

f0st3r · January 19, 2011

I have found most Chevron stations in my town are ethanol free, thus I only run Chevron gas in my truck. So far I am getting about 16mpg, mostly city on 100% pure gas.

jaslo · January 19, 2011

Looks like 91 octane only is ethanol free in my area. And plus its 30 cents or more to fill up with 91. But I will have to give it a try to see if I can some better gas mileage.

music · January 19, 2011

It always amazes me to see "11 to 12 mpg" listed for the 5.3, even city-only driving. I get 10 to 11 towing a 7k lb camper @ 60/65 mph. Must be the colder weather and no time to warm up?