For me i have been consistantly getting 15km/l for the last 2 tanks after i change to carlube 5-40w synthetic oil and the last tank my car was left idiling with aircon on for about total of 2 hours with wife and kid inside while i go for errands and on my way back from jb jam on the causeway if not i think can easily get 16km/l......for me i used the hard break in for my engine during the first 1k running in period...during run in is 12km/l getting better with each tank.....dun fight against slopes where possible i go around 90 normally but i can be a bit siao sometimes wack until 5k rpm sometimes enjoy the adrenalin of driving fast fast

1) % highway/city driving? 70/30
2) Brand and RON petrol used? mobil 5000
3) Tyre Pressure? Front 270, Back 250
4) Driving with air con turned on or off? Air con on 100% set temp at 23-24
5) Drive mostly during the day or at night? 50/50
6) Brand of engine oil used? carlube 5-40w
7) Mileage? 8k+
8) How many people are usually in the car or just yourself? 3-4ppl
9) Any modifications done to your car? ez-stab and spark bridge
10) Do you use any after market additives? never before.