FPS Controller problems

Read my latest comment for info..

This is the code I have the main section of problem is in the function Update

 //Garth's FPS Controller
 
 private var currentSpeed : float;
         var walkSpeed : float = 5;
         var runSpeed : float = 9;
         var gravity : float = 20;
 private    var sprinting : boolean;
         var airControl : boolean = false;
 private var playerControl : boolean = false;
         var jumpTimer : int;
         var limitDiagonalSpeed = true;
 private var moveDirection = Vector3.zero;
         var jumpSpeed : float = 8;
 private    var inputX;
 private var inputY;
 private var inputModifyFactor;
 private var myTransform : Transform;
 private var falling : boolean = false;
 private var fallStartLevel : float;
         var fallingDamageThreshold : float = 10.0;
         var grounded : boolean = false;
 private var controller;
         var sprintTimer : float = 0;
         var playerName = "New Player";
         var jumpLimit : int = 30;
         var jumpHold : float = 30;
         var jumping : boolean;
         
 
 function Start () {
     controller = GetComponent(CharacterController);
     sprinting = false;
     currentSpeed = walkSpeed;
     myTransform = transform;
     sprintTimer = Mathf.Clamp(10,0,10);
     jumpTimer = jumpLimit;
     jumping = false;
 
 }
 
 function FixedUpdate () {
     inputY = Input.GetAxis("Vertical");
     inputX = Input.GetAxis("Horizontal");
     inputModifyFactor = (inputX != 0.0 && inputY != 0.0 && limitDiagonalSpeed)? .7071 : 1.0;
     grounded = (controller.Move(moveDirection * Time.deltaTime) & CollisionFlags.Below) != 0;
     
     if (!Input.GetButton("Jump")) {
             jumpTimer++; 
             jumping = false;
     }
     else if (jumpTimer >= jumpLimit) {
             jumping = true;
             moveDirection.y = jumpSpeed;
             jumpTimer = 0;
     }
         
     if (falling) {
     falling = false;
     if (myTransform.position.y < fallStartLevel - fallingDamageThreshold)
         FallingDamageAlert (fallStartLevel - myTransform.position.y);
     }
     
     if (airControl && playerControl) {
         moveDirection.x = inputX * currentSpeed * inputModifyFactor;
         moveDirection.z = inputY * currentSpeed * inputModifyFactor;
         moveDirection = myTransform.TransformDirection(moveDirection);
     }
     if (!falling) {
         falling = true;
         fallStartLevel = myTransform.position.y;
         }
     moveDirection.y -= gravity * Time.deltaTime;
     
     if (sprinting == true) {
     sprintTimer -= Time.deltaTime;
     }
     if (sprinting == false) {
     sprintTimer += Time.deltaTime;
     }    
         
     if (Input.GetButton ("Jump")) {
     jumpHold -= 1 * Time.deltaTime;
     }
     if (jumpHold <= 0 && !jumping) {
     jumpHold = 30;
     jumpTimer = 30;
     }
     if (sprintTimer >=10) {
     sprintTimer = 10;
     }
     if (sprintTimer <= 0) {
     sprintTimer = 0;      //Fix sprint timer..? add a cooldown or something like that
     }
                                                                                   
 }
 
 function Update () {
     if (Input.GetAxis ("Vertical") > 0) { //Forward
      transform.Translate(Vector3(0,inputY,currentSpeed) * Time.deltaTime);
     }
     if (Input.GetAxis ("Vertical") < 0) { //Backward
     transform.Translate (Vector3(0,-inputY,currentSpeed) * Time.deltaTime);
     }
     if (Input.GetAxis ("Horizontal") > 0) { //Right
     transform.Translate (Vector3 (0,0,0) * Time.deltaTime);
     }
     if (Input.GetAxis ("Horizontal") < 0) { //Left
     transform.Translate (Vector3 (0,0,0) * Time.deltaTime);
     }
     
     if (Input.GetButton ("Run") && Input.GetButton ("Vertical") && sprintTimer >= 1 && grounded == true){
         currentSpeed = runSpeed;
         sprinting = true;
     }
     else {
     currentSpeed = walkSpeed;
     sprinting = false;
     }
     
     if (Input.GetButton ("Jump")) {
     jumpHold -= 1 * Time.deltaTime;
     }
     if (jumpHold <= 0 && !jumping) {
     jumpHold = 30;
     jumpTimer = 30;
     }
     if (sprintTimer <= 0) {
         currentSpeed = walkSpeed;
         sprinting = false;
         sprintTimer = 0;        
     }
     //Printing Section
     //print ("Speed = " + currentSpeed);
     //print ("Players Name = " + playerName);
     //print ("Sprinting = " + sprinting);
     //print ("Jumping = " + jumping);
     
     }
 function FallingDamageAlert (fallDistance : float) {
     print ("Ouch! Fell " + fallDistance + " units!");
     //Add sounds effects! + Health System
 }
 @script RequireComponent(CharacterController)

Any suggestions on what I could change to make the script better would be appreciated aswell

(Code updated to match question in the latest comment i made)