The most obvious reason which comes to my mind according to my knowledge is that the R18 engine which is in the Civic requires better quality of fuel compared to M13 of the City. Therefore it behaves like this.
There may be other reasons as well, but this one wins my vote.
As time passes the engine and the ecu become accustomed to what is being fed to them and the parts also come into proper running and settle down resulting in the car to settle down as well.
But then again one can only judge after driving what you're referring to because i have a 1100km driven Civic which drives just fine.
It had acceleration jerks in the first 200 or so kms but now Alhamdulilah all is ok.
Sent from my iPhone using PW Forums