I recently changed my veh's engine. Installed l13a engine. Veh is 2007 Honda city. Everything is fine except fuel mileage which is hardly 9 to 10 kmpl n city with AC on. Changed spark plugs, cleaned throttle body. Mechanic also checked the emissions through some kind of machine and said everything is ok. Installed new tyres. Went back to steel rims yet the problem persists. Any guidance please.