During hard accelerations with RPM above 3000, the engine (06 f150 5.6) is stuttering during continued acceleration. Very intermittently it will trigger code P0300, random misfire. I checked the temp of cats during those high rpms and they are reading between 1,700 to 1,800 degrees. Sign of a clogged cat? Plugs and cops changed last summer along with fuel filter. Note sure what else to check.