First I should admit, I have been having some issues with the car running rough, idling rough, uneven firing, and being overall disagreeable. I was pretty sure something was going on, but haven't diagnosed what just yet.

After doing some talking to some people around town, I decided to get some gas on the way home from work yesterday, as I had about 3/8 of a tank left. Same ole stuff, 91 octane, except, one small difference.

2 words:


The car purred like a kitten on the way to work this morning.

This proves to me that this car fights and kicks every second for every inch that it HAS to run on E10, which was in EVERY winter blend that was in town.

I am so puzzled as to why it would make such a big difference in driveability. What is different in newer cars that makes them run E10 any better?

I am going to be screwed if E15 is forced on us.

90% of what you put in is gasoline. The other 10% is alcohol.

But why do newer cars not seem to have drive-ability issue? What has changed in the last 20 years?

i think it has something to do with the flash point. alcohol ignites at a lower temperature.

Ethanol (blended fuels) also absorbs moisture. Metal gas tank rot out easily if you dont use water remover'* with ethanol fuels. A fuel staybilizer (made fore ethanol fuels ) added to tank does wonders a few times a year if you have to run blended fuels.
I personally will pay more for ethanol free gasoline'* and use them exclusively at 94 octane chevron stations here. I dont mind paying more, especially when the fuel mileage is better with non blended fuels.
I believe the cylinder temps are also higher with blended fuels as well.

Because of more tolerant fuel system components, and more importantly, better tuning. I'm not sure what model year the manufacturers began modifying cars to handle E10.

As far as E15 goes, word is that it will be safe for 2001 model years and newer. The older cars may or may not have issues. I did a quick Googling and found a fair number of people (somehow) running not just E15, but E85, in old engines without a problem, so I guess -- literally -- your mileage may vary.

Personally, I'd stick with this E00 station if that'* what your car likes best. You might want to try a bottle of fuel system cleaner and give E10 another shot.

newer cars run like junk too, my monte feels like it has plugs with 200k on it in the winter. and goes from 32mpg average local to 28-30

Not sure if it is true, but newer cars have stainless fuel lines instead of plastic/nylon/rubber which will degrade due to the Ethanol if above 10% fuel mixture, otherwise any car can burn E85.

E85 also does not have the mileage of Ethanol free fuel, in other words, you will burn more ethanol to go the same distance. (about 15-20% more fuel to go same distance)

it was more for me, e10 gas i get over 30 and e85 was down around 20. my monte has the LZE 3500 e85 engine.

That'* what I said, the more ethanol in the fuel, the less gas mileage....