Not to be your nastly ol' grammar school teacher, but I
think the problem here is vocabulary.

What do you mean by "idling"? "Idling" means the car is,
say, sitting at a stoplight with you in it, the engine
running, but at an RPM of around 750 (that number will
depend on the year and model of Honda).

Do you mean the car runs at a higher RPM than it should when
sitting at a stoplight?

What's the year and how many miles are on your Civic?

Is it up to date on maintenance such as coolant replacement,
ignition wire replacement, spark plug replacement, etc.?