My run in with random misfire codes was broken valve springs. It costs nothing to pull the valve cover off and check the valve train while rotating the engine. If you have a way to test compression- thats even better. Start there. If your tests/inspection yield nothing, you may have to go into the engine. I personally have not seen an injector or coil pack throw a multiple misfire code, but I do not work on strictly chrysler products every single day.
A cranking compression test will not always show a broken or weak valve spring as it may have enough to contain "static" compression but not running with the pressure of combustion
