Bro you need to check for following:
- Engine oil being poured (always pour in 0w-20, 5w-20 or lastly, 5w-30, fully synthetic engine oil, from some reputed brand, and make sure that it is 100% genuine and original, and meets latest API SN / SN Plus, and / or ILSAC GF-5 criteria). If engine health is perfect, switch engine oil brand and grade after engine flush.
- Always use 100% genuine and original, OEM filters (air filter, AC / Cabin filter, oil filter, etc.). Check the condition of filters, and take necessary action accordingly.
- Check for throttle body, spark plugs, catalytic converter, etc.
- Replace transmission oil, if not replaced in recent times, and if you have used it for ~40,000 Kms.
- Check tyres pressure and maintain it as per OEM recommendations.
- Check wheels balancing / alignment, at least for once.
- Let go of any additional weight in your car.
- Lagay hathoón brakes service b karwaa lein (if not done previously).
I hope, by following above steps. Your fuel efficiency will become better. Thank you.