99 accent bucks, or jumps while driving

Last week i was driving like 55mph, car started to like buck or jump a little while driving would do it for justa split second, but at least 2x a minute, it did this before last september, I added feul injector cleaner and it seemed to go away, so I then added injector cleaner again, this was saturday, cut to today friday on the way home from work it started doing it again. What can be causing this, only way i can describe it as it bucks or jumps while driving steady or accelerating

Last week i was driving like 55mph, car started to like buck or jump a little while driving would do it for justa split second, but at least 2x a minute, it did this before last september, I added feul injector cleaner and it seemed to go away, so I then added injector cleaner again, this was saturday, cut to today friday on the way home from work it started doing it again. What can be causing this, only way i can describe it as it bucks or jumps while driving steady or accelerating
My 99 Accent did this also and it turned out to be the throttle position senser. Replaced it and now it runs great