this is about the best suggesrtion ive seen, seafoam wont help, its not a clogged injector

toyota has codes for injectors, a misfire is seperate. it is actually as simple as it sounds-#3 is not firing

check coil packs, all wires going to coils, make sure that if you swap em around you remember wheich is which,
toyota also will flag misfire if compression is abnormally low in a cylender