intermittent misfires with check engine light coming on and then going off

check for vaccum leak in the intake system, loose or corroded ground wires, fuel pressure regulator, also have the codes read at your local autoparts store for free, find a good service center that looks for the problem before the medecine, cleaning the head will not solve this problem,

Check/ clean the maf sensor & its connector. Try spraying it with fast drying contact cleaner.