Change the spark plugs, the petrol quality is so bad that 100,000 kms spark plugs gets totally corroded within 30 to 40k mileage. I get all my maintenance items from Imperial Motors they offer genuine and high performance exclusive replacement parts such as spark plugs, transmission fluids, engine oils, filter belts and brakes. The genuine plug is ILMAR7A8 which is around Rs.2500 (genuine). There is a copy of the spark plug from China which is sold for Rs.1000-2200 and ensure to get the genuine plugs to avoid getting ripped.
You can contact Imperial Motors at 0345-2823350