ECO mode blunts throttle response and kicks down the A/C (if on) to save gas. That's all it does. You're not saving gas by driving with it off, especially if you feel like hot-footing it.

 

My own opinion is that ECO is more marketing gimmick than an effective fuel saver. In my case since I do 90% highway driving ECO does nothing for me. There's really not much that ECO can do since Honda has already squeezed out the maximum efficiency in the car as is. ECO will under certain circumstances provide a small improvement in fuel economy by sacrificing a small amount of performance somewhere.

 

I updated my previous post - using the DEFROST operates the A/C reducing mpg for those geographies that don't use A/C as often in the spring/fall (like Upper Plains and New England areas of the USA).

 

Wow! I had no idea. Thanks for the tip... I have had to use defrost a few times lately, but not for long at a time.

 

I thought "winter blend" was a scam they pushed onto us poor folks out here in CALI. I guess the rest of you guys are equally as unlucky to have to pump this crap gas during the winter months like us out here?

 

I've personally seen a 1-2 MPG penalty with NOT using ECON mode on my commute. YMMV

 

I didn't think y'all had winter blend but after reading this article I see it was an attempt to lower gas prices.

https://www.popularmechanics.com/car...ence-13747431/

Yes, the winter already sucks for driving and then we have this crap fuel they give us. You get diluted gas and only 91 octane!! We at least get 93 but its been in the 30's lately so not great for driving. I'm ready for Spring time.

 

1-2 mpg is what I would consider noise level - not worth noticing.

 

My 08' CRV was getting 27mpg all summer, now 24.7. My 16' EX Fit was averaging 38.3 via the past owner, I am now at 33.4. And I drive light footed, but not grandma style.

 

Out here on the Oregon coast, the temperature varies only about 30 degrees. We only occasionally get into the 30s. But my mgp goes down quite a bit with even a ten-degree drop. I don't know if we get winter gas. During the summer when it gets way up into the upper 60s, we see 42 mpg pretty often, and never below 38 mpg. Most our driving is on hwy 101 at 55 mph. But here in the dead of winter when the temperature drops into the lower 40s, our mpg goes down to 33 to 36 mpg. But I wonder... In my case I have been getting oxygen sensor error codes now and then that clear themselves after a few days. I don't think it's the cat. conv. My gues is that one or both of my oxygen sensors is close to being out of tolerance. So... I have considered that some of my reduced mpg might be due to oxygen sensor failure. My Fit is a 2015 with CVT and 150K miles. It's run great all along. I changed the plugs at 100K, but the old ones looked pretty darn good for that many miles. Anyway, my 2-cents worth.

 

Oxygen sensor replacement is probably a good idea based on your mileage and intermittent errors. As far as winter mileage goes that is a crap shoot. The EPA dictates SUMMER MIX values based on state and county. Summer mix has more BTUs per gallon and better mileage. Summer mix dictates in most locations starts May 1 and ends Sept i5. When the dictate is not in effect, the gas companies can sell whatever they want and usually sell the cheaper less BTU mix.
Other than Oregon I do not know what is dictated for your county. You can go to the EPA website and look up. your county. When you see the number that is RVP or Reid Vapor Pressure. A lower number is better. Octane has very little to do with mileage.
If you are in the Peoples Republic of California) ignore everything I said here, They do things different under CARB (California Air Resources Board). I have never looked up their procedures as I try to stay away from that state even though most my family is from there.

Here is a place to start if you are interested. There is a more detailed chart bby county also on their site.
https://www.epa.gov/gasoline-standar...vapor-pressure