Salam,Dear brothers. Please help me out here. My car has been driven in cng till now and it was giving me very bad mileage so I opted for petrol. It's good now. I need you people expert to tell me what kind of mobile oil is best for my engine. it's 1000cc, automatic. It has been driven for more than 2 lakh kilometers. Engine is in good condition. No carbon particles emission. 02 Sensors all normal. Please suggest me which mobile oil is best which maximum fuel efficiency. Thank you.