I would swap the COP on #5 with the one on, say, #1, clear the codes and then see if the problem reappears and if it does, determine if it stays with the cylinder or follows the COP.
To clarify: The COPs and possibly even the PCM can be damaged if the COP is run without a plug present at all. Although COPs have the ability to generate very high voltages (tens of thousands of volts), the amount of voltage actually generated will depend on what it takes to ionize the smallest gap in the circuit. This is normally the plug gap (e.g. ~0.054"). With no plug, the "gap" is massive and the voltage in the coil can go high enough to blow through the internal insulation before the "gap" breaks down. The resulting Inductive spikes can also play hell with the coil driver in the PCM.
A misfire only means that the cylinder failed to contribute on the power stroke. It could mean that the plug is fouled (e.g. shorted across the terminals), that the coil is unable to generate enough voltage to ionize the plug gap sufficiently to get a spark there, the fuel mixture in the chamber is wrong (too rich or too lean), there is insufficient compression on the cylinder and so on.
The easiest thing to try is to move the coil and see if the problem follows it.