frankly i wud consider 8km/l as lower acceptable range on this car.
get it scanned to find out any codes.
Clean the MAF sensor in the air intake box using electric contact cleaner only ( wd40, petrol diesel and carb cleaner will kill it)
as the AFR of ur car is set through a manula timpot installed on the right front strut column, u can do an exhaust gas analysis done to set it properly,
besides if the car is running okay with no hiccups, leave it as it is