Well Replied. Thanks for help.(H)
I faced some problem related to backfire(sound came from silencer) when car slows down from a high speed. recently i got tuning, and came to know that one of 8 plug was not replaced by mechanic(by fault) in previous tuning. 7 plugs(NGK) were good, and 1 plug was in worst condition. the mechanic just changed only the faulty plug. now, after a long return trip of about 350+ KM, the backfire problem seems to gone.
i guess in my situation, the problem is not because of ignition coil. but its due to the one faulty plug which was not replaced before.
What do you think?