How to handle camera view for avoiding jerking.

Hi, I am working on 2D game in Unity 4.3, I have long road image and when I run car with camera onto it, In middle of Image car sprite hide and then show for split second, I added other road sprite image just to check whether Problem is in Image or something else, it still generate jerking for split second on each image. I don't know why this happen. I set Camera on bit above and back of the car so that I can see car. Camera settings are all default with Prospective Projection. I don't know why this happening. I also show code below. Kindly help me on. Thanks in advance.

 float distanceFromPlayerCar =0.0f;
     float subtractor=0.0f;
     public Camera playerCarCamera;
 void Start () {
         distanceFromPlayerCar = transform.position.z;
         subtractor=0.3f;
     }
     
     void FixedUpdate() {
         distanceFromPlayerCar = distanceFromPlayerCar + subtractor; 
         transform.position = new Vector3(transform.position.x,transform.position.y,distanceFromPlayerCar);
         playerCarCamera.transform.position = new Vector3(playerCarCamera.transform.position.x,playerCarCamera.transform.position.y,distanceFromPlayerCar-2);
 }

This code script is attached to player car Object.