ydmdog

I am getting intermittent jerking from random misfires(obd reading p0300) that resets after 5 seconds while driving (usually on fwy). I replaced all the igniters about 1 year ago and since then I had the mass air sensor give me a fault (p0171)which I bought a special(at least said it was)cleaner for which I removed and cleaned 2 months ago which seemed to work at the time. I am wondering what kind of problem I have that can reset itself and not return for 50-100 miles?