Thank you so much Sanaullah for the detailed answer. Let me answer your questions below:
Do let us know how you calculate the fuel average.
Answer: (I filled 25 liters and then after 170 KMs again I filled 20 liters, 25+20=45 my car given me 340 KMs so 340/45 = 7.5 KM/L)
Change the Petrol pump and see if that makes a difference. Which petrol company are you currently using?
Answer: (PSO)
Considering your car is a 2003 Model it might have a swapped engine....
Answer: (Own Engine)
Change your Air filter and see if a blockade has been installed if the car was or is being used on CNG. It can also be in the shape of tape which covers the air cleaner box allowing less air going towards the intake manifold. If you find a blockade remove it!
Answer: (Through out Petrol, and recently tuned with all filters and oils changed even CVT oil replaced with tested all sensors)
Get your throttle body, MAP/MAF and Oxygen sensors cleaned with a good cleaner. Also, get the IAC Valve cleaned, make sure to lubricate it with a few drops of ATF oil after cleaning.
Answer: (Let me ask with the workshop owner which I've recently tuned car)
Use STP "Complete Fuel System Cleaner" or any other good ones you can find. For better results use it more concentrated.
Answer: (Sure let me use fuel cleaner)
Change the fuel filter. Use genuine fuel and air filters.
Answer: (Recently changed)
If all this doesn't improve your fuel average, consider changing your driving style.
Answer: (I've checked with all the driving styles, like slow acceleration, fast acceleration, with AC, without AC, etc...)
Thanks once again for the response.
Best Regards,
Umair Khalil