how to move your enemy?

So I have a script where my enemy moves up and down. then I wrote a script for it to move to the left. I would like my enemy to move up and down as it moves to the left however if I use the script where he moves up and down he won't move to left and if I use the script where my enemy moves to the left he won't move up and down I was hoping is someone can point me in the right direction to fix this dilemma.

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class Pole : MonoBehaviour
6. {
7.       public float speed;
8.     Vector3 _startingPos;
9.     Transform _trans;
10.     void Start()
11.     {
12.         _trans = GetComponent<Transform>();
13.         _startingPos = _trans.position;
14.     }
15.     void Update()
16.     {
17.    
18.     _trans.position = new Vector3(_startingPos.x, _startingPos.y + Mathf.PingPong(Time.time, 3), _startingPos.z);
19.  
20.         transform.Translate(Vector2.left * speed * Time.deltaTime);
21.  
22.     }
23.  
24. }
25.  

 

you can let the x-position stay the same here and don't change it twice.
_trans.position = new Vector3(_trans.position.x, _startingPos.y + Mathf.PingPong(Time.time, 3), _startingPos.z);

 

You sir are a master Among Masters once again you have helped me thank you.