misfiring. checked in on a diagnostic cylinder one is coded misfiring on 2006 Hummer H3

do I have to replace both the coil pack and plug. Is the a problem with the head?

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2 answers
I have a 2006 H3 Hummer and had same problem, had to change all Ignition coils on engine, easy fix same coils fit 5 cyl chevy traverse.
Here is some info about the misfiring cylinder: http://repairpal.com/OBD-II-Code-P0301