Caravan 3.8 p0300 & p0302

[1987ss]

I recently acquired a 04 grand caravan with 130k on it today i got off freeway and was sitting at light and i felt a pretty significant intermittent miss so i had it scanned and came back with those 2 codes and a previous evap code in wich i was aware of. Im gonna change plugs and wires in a.m. and possibly run sea foam threw brake booster vacuum. If there's something elese i should look at for those codes could someone please comment and tell me thanks!! I tried to clear codes and cel stayed on didn't go off and come back on it stayed illuminated??

[1987ss]

I ran seafoam threw brake booster vacuum about 2/3 of a bottle (more than usually), i removed and cleaned throttle body, changed pcv valve, spark plugs and wires. No check engine light after driving 60 miles and no p0300 p0302 & p0442 so so far so good..