Suzuki cultus fuel average issue

[shahmeert]

Hello everyone.
i own suzuki cultus 2012 efi. i am really troubled by the drop in the fuel average. i drive on long almost everyday from bahria town karachi to karachi main city having almost 100+ km running each day. my car is now giving very bad average which is almost to 9-10/km with a/c on long. can anyone please advise me how to improve fuel average on long because it is very less and i have no knowledge about cars. thank you

[engnr.mubashir]

What oil grade you are using.
When did you have changed plugs.
How is your car running I mean running smoothly or struggling while picking up from stop.
Do you feel car is heavy while accelerating.
Get the MAP sensor checked most common cause of poor fuel efficiency.
Als air intake temperature sensor.
Get your o2 sensor checked too.
Get you car’s tappet adjusted and that should be done on dead cold engine.
When you have changed fuel filter of car and injectors cleaned. How often you get air filter cleaned and what brand you are using.
My cultus is giving me 18.5 to 19.5 with AC on @ 90 to 100 km/h speed loaded with 3 passengers at back and trunk full of luggage. If I go above 100 it starts to drop to 16.5 to 17.5 average.

[shahmeert]

i use 20 / 40 grade oil. can you pleases recommend which grade oil from which brand is the best.
plugs were changed around 10 months ago.
when there are more passengers then the car feels heavy while accelerating.
ill get the sensors checked aswell.
thank you

[engnr.mubashir]

Who told you to use 20 40 oil ? 10w30 from caltex is best affordable for normal oil.
According to you journey plugs have completed their life change them. Buy from authentic source because chinese copy of ngk &denso plugs are being sold as genuine.
I’m asking alone or 2 person driving experience not with passengers.
Get other things sorted out too not just sensors.