2007 GC 4.7L FlexFuel: E85 vs Regular
 

I just bought my first GC, a 2007 Laredo 4.7L E85 FlexFuel motor. This is the 1st vehicle I have ever owned with a FlexFuel motor. The owner's manual states that it's not a good idea to alternate fill-ups with E85 ethanol and non ethanol gas. The first thing I had to do the day I drove it home was fill the tank so I found a station with regular non-ethanol gas and filled it. I had to drive it 1.5hrs home and it performed fine, got 17.6MPG avg. on the trip and since, still on that 1st tank of non-ethanol gas. The previous owners usually filled it with E10 87 octane. I don't think E85 fuel is available anywhere around here.
I realize that the 4.7L V8 in my GC is specifically designed to use E85 ethanol fuel but is it okay to regularly use non-ethanol gas in a E85 FlexFuel motor?

Flexfuel is designed to run on either e85 or gas so running just gas is fine.

The name FlexFuel means that the computer system has the programing to monitor cylinder temperatures and performance output to adjust the mixture and spark to burn whatever you put in it. Of course, not meaning diesel! It would probably burn straight ethanol, but that's not sold in the US except for racing. Just remember that ethanol contains less latent heat per liter than gasoline, so you'll use more per mile.

You're better off running gas.

Yup. This. Just run 87. I've seen cars with issues when they ran 85. And probably what Dave said. Computer not use to it when its ran once and a while

Okay, thanks for the responses. I have been reading up on the FlexFuel motors and they seem to be designed to run best on the lower octane ethanol gas. Most of the gas stations here in Lynchburg and surrounding areas have E10 but I've never seen anything higher. Ever since I discovered there were a few stations selling non-ethanol regular & super unleaded I have been using it in my XJ and other vehicles. I immediately noticed an increase in gas mileage and going up long hills seemed to be easier. I'm gonna use it in my 2007 GC for the time being.

Your mileage will go down with E85 because it has less heat energy than gasoline. E10 has less energy thane non alcohol gas. If you can get alcohol free gas where you're at be thankful, we don't have that in California.

Wish I had non ethanol by me

In NY you used to be able to get non-ethanol gas but it was super-unleaded 97 octane and cost about $.60 more per gallon than 87 and 84 octane E10 was also available for whatever reason IDK.

Now, only a few places have the 97 non-ethanol and it costs about $.70 more. The problem with ethanol fuel is most engines made before 1994 don't tolerate it very well, especially small engines. I've had to rebuild the carb and fuel pump on my 92 lawn tractor every year because they quit working and leaking because of it. I haven't been able to find compatible retrofit seals for it and now am having trouble finding non-ethanol fuel. I even tried a cheap Chinese electric fuel pump on it and it only lasted a week!

87 E10 seems to be the US standard now and 94 E10 is the premium fuel. The guys with the WWII Warbirds can only get 100 low-lead and they run like crap on it! They were built for 115-145 "purple juice".

dave1123, hey, Schenectady born & raised (county, not city), Siena College grad. There are plenty of places in the Empire state where you can find non-ethanol gas but www.pure-gas.org lists only two in Syracuse:

East Syracuse SUNOCO 91 Expressmart 315-437-2485 6396 E Molloy 2015-10-05

Syracuse NICE N EASY 91 Nice N Easy 315-458-5720 6392 E Taft Rd 2015-04-29

but I see 3 in Auburn, 3 in Liverpool(including a Stewarts), and two more in Cicero with some showing 91oct! check out the site to see if you can find one closest to you. You may not be able to find 97oct. but still ANY grade of non-ethanol is better than the corn based garbage from my experience and you can always add some Octane boost to your tank.
So far so good with my '07 GC. Ever since discovering pure-gas.org and finding some major chain + mom&pop gas stations here in central Virginia that carry it I have used it exclusively all of my small equipment, my four-wheeler(that's the redneck x-lation for "ATV" or "quad"), my Jeeps/Trucks and anything that uses gas! no regrets & worth the few shekels more than the less plant based crap.