I also got honda city 2010 automatic . there is no knocking issue in my car but pick of my car is like driving a mehran with ac on cng .... My car fuel avg was 8.2 before 10km check up after that its 7.2. i complained to honda fort they say use hi-octane.
Fuel gauge Problem :
When low fuel light is on .. and I fill my tank with 11 litre petrol .. the fuel gauge indicator still remain on low fuel and my low fuel light does not go off .... If i again fill my tank with 5 litre of petrol the indicator pointed on half gauge..