hi, my 95 neon hesitates from a heavy take-off, but if you ease onto the throttle, it accelerates normally. what could be wrong?

 

having the same problem with my 96 right now, accelerates fine when i ease into it, but if i put the pedal to the floor it doesnt really go anywhere, i have a bad rear o2 sensor, im starting there, if you find out what is causing this let me know!