Hey guys,

Sorry if this post is up, I have searched for days now, but no luck finding a problem similiar to mine. Maybe I am using wrong keywords.

Anyways I have a 1992 300ce ~200k miles on it, and speeds above 45 it starts to jerk back and forth very heavily when I maintain a constant speed. If i accelerate or decelerate the car runs smooth. It also does heavy jerking right before 2nd to 3rd shifting (I am assuming it is a transmission issue).
This problem starting happening after I had my car smogged at a local shop.

The "jerking" is, as if someone where to step on the gas pedal quickly and then let go, very rapidly.

I have changed fuel filter maybe 3k miles ago (OES)
New ignition coil (OES)
New cam sensor (OES)
New crank sensor (OES)

Any advice will be greatly appreciated
Thank You.
Mike K.