Character movement working but dash is teleporting??

using UnityEngine; using System.Collections;

public class TileMovement : MonoBehaviour {

 public string LastMoveDirection;
 private float speed = 2.0f;
 public float dash_speed = 0f;
 public string RotateCharacter;
 private bool Rotated = false;
 [SerializeField] private Vector3 pos;
 private Transform transform;
 private CharacterController characterController;
 private Vector3 lastRoundedPosition;
 void Awake()
 {
     //Here we set the Values from the current position
     pos = base.transform.position;
     transform = base.transform;
     characterController = this.GetComponent<CharacterController>();
 }
 //void OnControllerColliderHit(ControllerColliderHit hit)
 //{
 //    Debug.Log("Hit somthing " + hit.transform.tag);
 //    if (hit.transform.tag == "FloorTile")
 //    {
 //        hit.gameObject.GetComponent<TileRotation>().FlipTile();
 //    }
 //}
 void Update()
 {
     Movement();
     // transform.position = pos;
 }
 private void Movement()
 {
     //If we press any Key we will add a direction to the position ...
     //using Vector3.'anydirection' will add 1 to that direction
     //But we Check if we are at the new Position, before we can add some more
     //it will prevent to move before you are at your next 'tile'
     if (Input.GetButtonDown("Horizontal"))
     {
         if (Input.GetAxisRaw("Horizontal") == 1) //&& rigidbody.position == pos)
         {
             // pos += Vector3.right;
             transform.rotation = Quaternion.LookRotation(Vector3.right);
             if(Input.GetButton("LeftShift"))
             {
              characterController.Move(Vector3.right*dash_speed);
             }
             else
             {
              characterController.Move(Vector3.right);
             }
             LastMoveDirection = "right";
         }
         else if (Input.GetAxisRaw("Horizontal") == -1)// && rigidbody.position == pos)
         {
             //   pos += Vector3.left;
             transform.rotation = Quaternion.LookRotation(Vector3.left);
             if (Input.GetButton("LeftShift"))
             {
                 characterController.Move(Vector3.left*dash_speed);
             }
             else
             {
                 characterController.Move(Vector3.left);
             }
             LastMoveDirection = "left";
         }
     }
     if (Input.GetButtonDown("Vertical"))
     {
         if (Input.GetAxisRaw("Vertical") == 1)//&& rigidbody.position == pos)
         {
             //  pos += Vector3.forward;
             transform.rotation = Quaternion.LookRotation(Vector3.forward);
             if (Input.GetButton("LeftShift"))
             {
                 characterController.Move(Vector3.forward*dash_speed);
             }
             else
             {
                 characterController.Move(Vector3.forward);
             }
             LastMoveDirection = "forward";
         }
         else if (Input.GetAxisRaw("Vertical") == -1)// && rigidbody.position == pos)
         {
             //  pos += Vector3.back;
             transform.rotation = Quaternion.LookRotation(Vector3.back);
             if (Input.GetButton("LeftShift"))
             {
                 characterController.Move(Vector3.back*dash_speed);
             }
             else
             {
                 characterController.Move(Vector3.back);
             }
             LastMoveDirection = "back";
         }
     }
     // characterController.Move(new Vector3(Mathf.FloorToInt(characterController.transform.position.x), 0, Mathf.FloorToInt(characterController.transform.position.z)));
     characterController.transform.position = new Vector3(
         Mathf.RoundToInt(characterController.transform.position.x),
         Mathf.RoundToInt(1),
         Mathf.RoundToInt(characterController.transform.position.z)
         );
 }
     //Here you will move Towards the new position ...
     //transform.position = Vector3.MoveTowards(transform.position, pos, Time.deltaTime * speed);
}