Hi, I have been using Mobil 1 in a 1 year old Suzuki Alto car with 998 cc 3 cyl K-Series gasoline MPFI engine. The recommended oil is 5W30. With 0W40 I have been experiencing a better responsiveness but FE has been decreased significantly say around 1.5 KM drop per liter of gasoline. With stock engine oil it used to return 16.5 kmpl but now with 0w40 its constantly returning 15 kmpl. And I also came to know this M1 0W40 oil contains relatively more amount of Zinc and Phosphorus which is not good for catalytic converter. Should I continue to use this oil up to next oil change or I should change the oil right now ?