Get the throttle body cleaned. There is a sensor attached below the TB (don't know what the knowledgables call it). Make sure it gets cleaned too.
I too am an owner of Honda City and faced the same annoying problem. After a couple thousand rounds to mechanics and cng tuneups, I finally got the culprit..... a choked air sensor under the throttle body. After a thorough cleanup the car purrs very very elegantly at idle now (H)
don't compare my 4 digit days old status to my single digit post count. I am just a silent listener/reader
the 'sensor i was referring to is called 'Idle Air Control Valve' and is located under the TB