my check engine light is on in my 2001 ranger, the code is p306, misfire in cylinder 6, what could the problem be?

 

bad spark plug
bad spark plug wire
Are the most common

Less common would be bad coil pack, swap #2 and #6 wires on coil, if new code is P0302 then replace coil pack

test #6 fuel injector with OHM meter, 11-18ohms is spec., it can usually be done without removing injector.

Last thing would be a compression test on all cylinders, see if #6 is 15% less than the other 5 cylinders