I have a rental for a month. I really like the car. I have noticed that when I am stopped at stoplights every 20 seconds, or so, the engine seems to do a little hiccup or shiver. I don’t have a better name for it. Maybe shake? There’s a little green tree logo in the dashboard, I don’t really know what that means and I’m probably not particularly interested in it. I’m asking not because of the rental car but I am strongly considering buying the car. Thanks for any help you can give

 

2018 Honda Civic EX L Coupe.
1.5L 1497CC L4 FI Turbo.
CVT transmission.
80,000 miles.
I'm having the same issue it seems. Problem just started yesterday, after pulling into my driveway (stopped, but still in drive) I noticed a pretty rough vibration inside the vehicle. Seats are shaking and a plastic bag I had on the passenger seat was going haywire. When the vehicle is in park, neutral or reverse the vibration does not happen. When in drive, sports or low the vehicle starts vibrating only when the vehicle is not moving. I found when the A/C or defroster is on the RPM raises and the vibration stop. My idle RPM when in drive and stopped is at roughly 600rpm (this is when vibrations occur) when the rpm goes up to around 675 plus the vibrations go away. When in park my rpm is at 700 and no noticeable vibrations. I'm also very curious on what is causing this.

 

Sounds like you have the car in economy mode (in regards to the green tree logo)