my car is having similar problem. let me try to tell what exactly happens, during driving my car suddenly starts vibrating and shuts down, then it never starts on petrol, if i am in luck and have CNG filled, i convert to CNG and it starts again. it never starts on petrol, after when i convert from CNG to petrol, it starts running on petrol. i dont know what is wrong and what to do. any help would be very helpful.