Weird Movement

Hello, I made a movement script. It is simple but it moves really weird like there is friction. How can i prevent that and yes I tried adding time.deltatime.

 #pragma strict
 
 var speed : float = 0.05;
 
 
 function Update () 
 {
     if (Input.GetKey("w"))
     {
     transform.position.z += speed;
     }
     
     if (Input.GetKey("s"))
     {
     transform.position.z -= speed;
     }
 }