If it's just that one cylinder misfiring, first check your spark plugs (I would replace them @ 105K miles) and your spark plug wires (ditto for replacement). Also check your fuel injectors by swapping two of the same color injectors (if the problem moves to another cylinder, your injector is bad). Only swap purple for purple, and green for green, don't mix the colors.
If none of those work, you should check your compression to make sure it is in spec, and also check for air leaks between intake manifold and cylinder head, and also between the two parts of the intake manifold (spray some unlit propane around these seams and if your engine noise/speed changes, you've found a leak).
If none of that stuff works, then you've got a wiring issue, which will be a PITA to track down (usually). The nice thing about a misfire in only one cylinder is that it really narrows down your troubleshooting.