have following problems in my Alto 2006 driven 55000Km
1 Car is mostly driven on petrol and Petrol average decreases from 10-11 to 7-8 and on CNG 125 -130 to 100-110
2 Car is maintained properly as oil change is after every 2500 to 3000 Km
3 Car has been tuned last week but still sometimes missing especially in morning