I was facing problems of stalling on petrol (perfect on CNG), after multiple advices had to replace fuel pump and 1 injector. Actually I became victim of bad petrol.
Got a kabli fuel pump for Rs. 2000. New chinese range from 1000~1500 but do not have good repute. I got a relay installed with CNG switch which now turns off the fuel pump when running on CNG, this will be good for future protection of fuel pump as mostly I run my car on CNG.