AI not realistic...

This is my code, i have a car game where the enemy car tries to crash into you and other enemy cars, but the problem is... THEY START FLYING AT ME WHEN I DO A JUMP! and the also go too slow. and when i hit them (its a crashup type game) they start going crazy! can anyone give me some help? D:

 var player: Transform;
 var waypoint : Transform[];
 var target : Transform;
 
 private var distance: float;
 private var currentwaypoint : int;
 
 function Start() { 
     player = GetRandomPlayer();
 }
 
 function Update () {
     distance = Vector3.Distance(transform.position, player.position); 
     if (distance > 1.5f) {
         transform.rotation = Quaternion.Slerp(transform.rotation, 
                                               Quaternion.LookRotation(player.position - transform.position), 
                                               Time.deltaTime * 4); 
         transform.Translate(0, 0, .05f);
     }
 }
 
 function GetRandomPlayer() : Transform {
     var players = GameObject.FindGameObjectsWithTag("Player");
     return players[Random.Range(0, players.Length)].transform;    
 }