Spark plugs of Passo are very common. Just go to mechanic and ask him to check its plugs. If these are very old then you can replace them with new ones. Can buy from market. Very commonly available. Get throttle body cleaner and ask mechanic to spare it well.
I am sure your Car is CVT. To get the best mileage, feed low viscose engine oil like 5W-20. Example is ZIC A+.
Or you can feed it 0W-30
These two are best available options to get the best mileage.
Check dip stick of gear oil. It has to be full. And if it need to change, then do it as well. But only replace it with CVTF.
Top up from good fuel station. If possible then mix 20~30% hi octane.
Keep full level of radiator water/coolant.
Use good quality oil/air filter. Specially blow the air filter once a month at-least.
Ideal tire air pressure is 28 psi. Tire width matter also.
Your car has electrical steering and doesn?t have separate power oil. Right?
if you car has ECO then its button will be available separately. you have to find it out somewhere close to steering.
does it has gear lever with steering or separate?