Car jerk n idling went dowm n up. help me thank u.

Hi everyone, I just bought my car aveo 5 LS hacknack. make in 2006. auto.

I haveb been driving for two weeks n recently I have this problem when my car is not moving n my gear is either at D or R.

the car will jerk n idling went down n up. The feeling like misfire. went to the car shop. they change spark coil n tranimission sensor with new start spark also change.

after driving for a week, the problem is back. anyone have any idea what is the issues.

thank you

So the revs will jump up and down a bit on the tachometer? Mine did that and I had to take out the throttle body and give it a good cleaning. Worked for awhile but since you cant remove the idle air control valve if will come back or at least did in my case.

Has anyone tried a drop of oil on the butterfly valve shaft where it enters the TB on both sides, just wondering if's it's a sticking butterfly....yes no changeable IAC is certainly not car owner friendly/ parts sales friendly though !