I have a 2018 CVT and I just keep it on all the time. The ECO green lights really help regulate your right foot. Throttle response is softened, but since it's always on I don't mind or care.

A side benefit to driving this way is that the ECO button turns into a "sport" button of sorts. 98% of the time I have ECO on ("Sport" off) in D, with the other 2% being ECO off ("Sport" on) in S with manual shifting enabled. Just makes for a little bit larger difference in performance (and another neat gizmo to press) when having a bit of fun with the car.

 

My understanding is that when you are in Eco Mode the car runs on only 3 cylinders which is suppose to give you an approximate 15% gas savings. The idle cylinder will alternate but I don't know if that is on the go or if the change takes place with a trip start. I'm not sure where I heard this but it must have been from the dealer.
I have never tested the mileage claim but I can say that I am seeing an approximate 15-20% improvement in gas consumption when compared to the 2011 Corolla I was driving before buying this car. I suspect at least a portion of that can be attributed to the Eco Mode.

I almost always use the Eco Mode and it definitely has a dampening effect on the throttle but it is still fairly peppy. I suspect one would fairly quickly adjust to the throttle sensitivity of whatever mode you use.

 

Cylinder deactivation? That's a fairly sophisticated system to implement, while the ECON mode is a much simpler system from everything I've read. It looks like all programming tweaks - blunting throttle response, changing shift points and cycling the A/C more often. I've yet to read about any ECON cylinder deactivation from any Honda-approved source - namely, their website and various Honda dealer websites.

 

I don't disagree with you and I don't have the tech knowledge to know one way or the other. As I said, I don't know from where I read or was told this but if it wasn't this site or the dealer, I don't know where it would have been from.

 

my GK feels like its always running on only 3 cylinders..

 

I've never read or heard that ECON mode makes the vehicle run on 3 cylinders.
I'm HIGHLY SKEPTICAL.

 

If ECON mode made the engine run on 3 cylinders Honda would have that in it's literature. They tried this once before and touted it as a "feature".

When I bought my 2008 Civic I was coming from a 1998 Accord V6. When I looked at the 2008 Accords with V6 the car was now significantly larger, much heavier and, to compensate for the added heft, now had 268 hp instead of the 200 hp in the 1998 model. In an attempt to keep the MPG higher, Honda had the engine automatically switching between running on 6, 4 and 3 cylinders. Despite this, the EPA city estimate was only 19 mpg!

I'm not sure how well that engine worked out but I don't think they're using that design anymore, so I guess that says something. I figured the added complexity would be just one more expensive thing to break so I went with the Civic. Glad I did.