Lincoln

My ls shakes alot when u turn on and when u start accelerating after a little gas it stops there os also a little knocking sound they had told me at auto zone when they checked the check engine lite it was a oxygen sensor and a spark plug i replaced them and nothing changed ther also erased the check engine light does anyone have any idea whats wrong or if it may be a huge problem

Could have a dirty gasoline filter- cracks in your spark plug wires causing it to misfire- when it is dark- start your engine- pop the hood and look for little sparks on the spark plug wires- d