Move player step by step

Hi im trying to move my player in WASD direction; when I press W i want that my player moves only for example 1 second or 15u in X axes and then i have to press again W to move it.

 using UnityEngine;
 using System.Collections;
 
 public class PlayerMove : MonoBehaviour {
 
     public KeyCode moveUp;
     public KeyCode moveDown;
     public KeyCode moveLeft;
     public KeyCode moveRight;
     
     public float moveSpeed;
     public Vector3 pointB;
     public bool moving = false;
     
     void Update()
     {
         if (Input.GetKey (moveUp)) {
             pointB = (0,transform.position.y + 10,0);
             moving = true;
         }
 
         if (Input.GetKey (moveDown)) {
             pointB = (0,transform.position.y - 10,0);
             moving = true;
         }
 
         if (Input.GetKey (moveLeft)) {
             pointB = (transform.position.x-10,0,0);
             moving = true;
         }
 
         if (Input.GetKey (moveRight)) {
             pointB = (transform.position.x-10,0,0);
             moving = true;
         }
     }
 
     IEnumerator Start()
     {
         var pointA = transform.position;
             
         while (moving == true) {
             yield return StartCoroutine(MoveObject(transform, pointA, pointB, moveSpeed));
         }
     }
 
 
     
     IEnumerator MoveObject(Transform thisTransform, Vector3 startPos, Vector3 endPos, float time)
     {
         var i= 0.0f;
         var rate= 1.0f/time;
         while (i < 1.0f) {
             i += Time.deltaTime * rate;
             thisTransform.position = Vector3.Lerp (startPos, endPos, i);
             yield return null;
             if (transform.position == pointB)
             {
                 moving = false;
             }
         }
     }
 }

But when I press any key doesn't works