all it was used for on the airbox was to open a small door for more air into the box at higher rpm. you just need it plugged in to keep that p01410 code away.
that misfire code need to resolved ASAP!!! start with new spark plugs fromMazda $4 each but they last for another 50,000 miles
coils from oreilly are $65 each, with best warranty around. obviously, you need 6 unless you want to take a VERY risky chance.
PCV valve should be replaced to prevent it from sucking your oil dry. you dont wanna run low on oil or your bearings will be shot.
since you are new im trying cover the known parts to pay attention to