Character having character controller is very jittery/shaking

My character is having a character controller which is very jittery while movement. i tried tweaking character controller values but nothing worked for me. It is an infinite runner game where the player moves and performs certain animations while moving as the player is standing there is no shaking but as it starts moving it jitters badly.

 public class PlayerMotor : MonoBehaviour
 {
 public static PlayerMotor Instance { get; set;}
 private const float LANE_DISTANCE = 2.5f;
 private const float TURN_SPEED = 0.05f;
 public GameObject Enemy;
 public GameObject StakeBoard;
   
 private bool isRunning = false;
 public bool magnetAttract = false;
 public bool Skateboarding = false;
 public bool SkateValue = true;

 //Animation
 [HideInInspector]
 public Animator anim;

 //Movement
 private CharacterController controller;
 private float jumpForce = 10.0F;   // how high player can jump
 private float gravity = 12.0f;    //Gravity makes the body fall down
 private float verticalVelocity;//This will be set for every single frame

 private int desiredLane = 1;   // 0=Left , 1= Middle , 2=Right

 //Speed Modifier
 private float originalSpeed = 8.0f;
 private float Speed = 8.0f;    // Player Speed
 private float speedIncreaseLastTick;   // Last time speed was increased
 private float speedIncreaseTime = 2.5f;
 private float speedIncreaseAmount = 0.1f;

 
 
 private void Start()
 {
    
     Instance = this;
     
     Speed = originalSpeed;
     controller = GetComponent<CharacterController>();
     anim = GetComponentInChildren<Animator>();
 }

 private void Update()
 {
     if (!isRunning)
     return;
     
 if (Skateboarding == true && SkateValue==true)
     {
         anim.SetBool("Skate", true);
         StakeBoard.SetActive(true);
         SkateValue = false;
     }

     if (Time.time - speedIncreaseLastTick > speedIncreaseTime)
     {
         speedIncreaseLastTick = Time.time;
         Speed += speedIncreaseAmount;
         GameManager.Instance.UpdateModifier(Speed-originalSpeed);
     }


     //Gather the inputs on which lane we should be
     if (MobileInput.Instance.SwipeLeft)
         MoveLane(false);
     if (MobileInput.Instance.SwipeRight)
         MoveLane(true);


     // Calculate Where we should be in the future
     Vector3 targetPosition = transform.position.z * Vector3.forward;
     if (desiredLane == 0)
         targetPosition += Vector3.left * LANE_DISTANCE;
     else if (desiredLane == 2)
         targetPosition += Vector3.right * LANE_DISTANCE;

     // Calculate our move dalta
     Vector3 moveVector = Vector3.zero;
     moveVector.x = (targetPosition - transform.position).normalized.x
 * Speed;  //where we should be - where we are right now  
 , directional vector


 bool isGrounded = IsGrounded();
     anim.SetBool("Grounded", isGrounded);


     // Calculate Y
     if (IsGrounded()) //if Grounded
     {
         verticalVelocity = -0.1f;
        
         if (MobileInput.Instance.SwipeUp)
         {
             //Jump
             if (Skateboarding == true)
             {
                 anim.SetBool("SkateJump", true);
             }else
             anim.SetBool("Jump", true);

             verticalVelocity = jumpForce;
            
             Invoke("Stopjump", 1.0f);

         }
         else if (MobileInput.Instance.SwipeDown)
         {
             //Slide
             StartSliding();
             Invoke("StopSliding", 1.0f);
             FindObjectOfType<AudioManager>().Play("slide");
         }
         
     }
     
     else
     {
         verticalVelocity -= (gravity * Time.deltaTime);

         //Fast falling Mechanics while in the air
         if(MobileInput.Instance.SwipeDown)
         {
             verticalVelocity = -jumpForce;
         }

     }
     moveVector.y = verticalVelocity;
     moveVector.z = Speed;

     //Move the player
     controller.Move(moveVector * Time.deltaTime);

     //Rotate the player to where he is going
     Vector3 dir = controller.velocity;
     if(dir!= Vector3.zero)
     {
         dir.y = 0;
         transform.forward = Vector3.Lerp(transform.forward, dir
     , TURN_SPEED);
     }

   
 }

 private void StartSliding()
 {
     if (Skateboarding == true)
     {
         anim.SetBool("SkateSlide", true);
        
     }
     else
         anim.SetBool("Sliding", true);

     controller.height /= 2;
     controller.center = new Vector3(controller.center.x, 
 controller.center.y/2,controller.center.z);
 }

 private void StopSliding()
 {
     if (Skateboarding == true)
     {
         anim.SetBool("SkateSlide", false);
     }
     else
         anim.SetBool("Sliding", false);

     controller.height *= 2;
     controller.center = new Vector3(controller.center.x, 
 controller.center.y * 2, controller.center.z);
 }
 private void Stopjump()
 {
     if (Skateboarding == true)
     {
         anim.SetBool("SkateJump", false);
     }
     else
         anim.SetBool("Jump", false);
    // controller.height *= 2;
  //   controller.center = new Vector3(controller.center.x, 
 controller.center.y * 2, controller.center.z);
 }
 public void MoveLane(bool goingRight)
 {

     desiredLane += (goingRight) ? 1 : -1;
     desiredLane = Mathf.Clamp(desiredLane, 0, 2);

     // Same As above to check on which lane palyer is 
     //if (!goingRight)
     //{
     //    desiredLane--;
     //    if(desiredLane==-1)
     //        desiredLane = 0;
     //}
     //else
     //{
     //    desiredLane++;
     //    if(desiredLane==3)
     //        desiredLane = 2;
     //}
 }

 private bool IsGrounded()
 {
     Ray groundray = new Ray(
     new Vector3(
     controller.bounds.center.x,
     (controller.bounds.center.y - controller.bounds.extents.y) + 0.02f,
     controller.bounds.center.z),
     Vector3.down);
     Debug.DrawRay(groundray.origin, groundray.direction, Color.cyan,
     1.0f);

     return Physics.Raycast(groundray, 0.2f + 0.1f);
         
 }

 public void StartRunning()
 {
     isRunning = true;
     anim.SetTrigger("StartRunning");
 }

 private void Crash()
 {

    
     anim.SetTrigger("Death");
     
   //  enemy.Instance.go();
     isRunning = false;
     GameManager.Instance.OnDeath();
     FindObjectOfType<AudioManager>().Play("dead");

     Enemy.SetActive(true);
 }
 private void OnControllerColliderHit(ControllerColliderHit hit)
 {
   switch (hit.gameObject.tag)
     {
         case "Obstacle":
             Crash();
             break;
     }

       

 }
 private void OnTriggerEnter(Collider other)
 {
     if (other.tag == "scene")
         GameManager.currentLocation.z = 0.0f;
     if(other.tag=="scene2")
         GameManager.currentLocation.z = 200.0f;
     if (other.tag=="scene3")
         GameManager.currentLocation.z = 400.0f;
     if (other.tag=="scene4")
         GameManager.currentLocation.z = 600.0f;
     if (other.tag=="scene5")
         GameManager.currentLocation.z = 800.0f;
    
 }

 }