Check engine light came on yesterday. Engine runs alittle rough. on 2005 Ford F-150

At highway speeds the check engine light flashes. It is going into the shop on Tuesday just wondering what I'm in for. Thinking maybe O2 sensor but I've read about catalytic converter ?

Asked by for the 2005 Ford F-150
Flashing C.E.L. indicates an engine misfire, most likely a coil on plug (cop) injector or spark plug problem.