Thanks mikmech n carstyle.
I have already visited Suzuki township motors n their cng mechanic told me to change 2 coils(each coil cost around 10000 rs.) and 2 injectors (each injector costs around 4000 rs).and said that the car will be like new one.so it will become a total of around 30000 rs.n it is a huge amount.so my aim by this thread is to get a 2nd opinion ,a reliable one.
in the market the Chinese coils costs 4500 a pair and Japanese 8500 a pair.so buying coils from market is a option too.