My 01 cavalier has 215,500 kms, Ive done full tune up, New fuel filter, air filter, oil changes done every 5,000 kms. I have a question This is what I am noticing this issue i am getting a mild surge idle, No mis-firing I am thinking it could be O2 sensor or plugged cat converter, Not sure, Also I believe the O2 sensors are basically best of my knowledge they are stockers, Also I have no check engine displayed. Also notice on on hwy speeds is like the same mild surge on throttle speed, I am thinking O2 sensors.

Any Idea's or hints guys thanks.