First, I really was referring to my Element. My two current Hondas are automatics: 2106 Pilot and 2013 Civic. I owned a 1999 Civic EX manual, but I never spent much time coasting in that car. I was still learning how to drive a stick; nothing fancy. Other than coming off the gas to glide to a stop and using my breaks as little as possible, I do not coast in neutral in my current cars. Besides, that little econ button does and better than passable job at increasing my mpgs without any help from me.

My Element however, that I owned for 12 years and hypermiled in for the last 8 of those years, was a manual, and yes, I coasted in neutral daily in that car. I didn't really mean to suggest that I had tested my "theory." I most certainly have and it had unequivocally resulted in higher mpgs to do so. Those are however MY facts and they are anecdotal (though totally representative of other hypermilers I know). Mileage may vary and you can get a different result than I did, but overall, in that 8 years, coasting gave me a 6-8 mpg boost. No lie. I went from getting 19mpg in the first few years to 26 mpg on average for the last 8. I lived in Vermont then and the roads are hilly, winding, and snowy so even with my Nokian tires, I still got vastly improved mpg. No special changes, gas additives, or other mitigating factors. I lived at the top of a hill at the end of a two mile dirt road that loved to wear out my brakes and CV joints, but caused no other real harm to the car.

I never once coasted with my foot on the clutch. It burns/wears out the clutch to hold it down like that without shifting into gear. In 298k miles in that vehicle, I replaced the clutch once (after 200k miles) and I never had engine or transmission trouble.

I hope that helps. If you have any more questions, just let me know.