I have a code p0303 it's a miss fire on my cylinder can anybody help me out

might not be the spark plug,possible ignition coil has failed,,but #3 is in the middle in the rear. copy and past the link below....clear the code,swap #3 COP with #4(middle front) COP,see if the code moves to #4(P0304),if so,then you'll know it's the coil and not the plug.if you need parts,see rockauto.com,same parts as local parts stores(OEM or Aftermarket) up to 50% less cost,very little shipping charge! EXAMPLE: rockauto,denso coil 673-8202.$48.79 plus shipping no tax(you choose from drop down menu shipping option.now autozone same oem coil as rockauto,denso coil 673-8202 $74.00 plus tax? www.wellsve.com/custom_searches/pdf/firing_order/Kia_truck_3.pdf