99 Mitsubishi Galant 4cyl running extremely rough?

I have a 99 Mitsubishi Galant 4cyl, and diagnostics say Cyl #4 is misfiring. It shakes back and forth when I take off from a stop, especially when it's cold. I've replaced the spark plugs, cables, and run fuel injector cleaner through. I think maybe the coils or fuel injector, or possible fuel filter, but could anyone help me please?