Accessing shader property breaks shader

Hi there I'm making a basic particle effect shader and would like to pass the position of my particle effect emmitter to the shader. I'm doing this via a script :

 using UnityEngine;
 using System.Collections;
 
 public class ParticleEmitterScript : MonoBehaviour 
 {
     public GameObject emitter;
     // Use this for initialization
     void Start () 
     {
         gameObject.renderer.material.SetVector("_Position", new Vector4(0,0,0,0));
     }
     
     // Update is called once per frame
     void Update () {
     
     }
 }

However when I attach this script my shader stops working as it should. If I attach this script to all particles in my system all particles will follow one path.

Here is my shader :

 Shader "Custom/ParticleShader" 
 {
     Properties 
     {
         _MainTex ("Texture", 2D) = "white" {}
         _Speed ("Particle Speed", Range (0,10)) = 0.5
         _Height ("Particle Height", Range (0,100)) = 80
         _ParticleSpread ("Particle Spread", Range (0,100)) = 20
         _ParticleSize ("Particle Size", Range (0,10)) = 7.8
         _ParticleSystemShape ("System Shape", Range (0,10)) = 1
         _Cutoff ("Cut Off", Range (0,1)) = 0.5
         _Fader ("Fade Point", Range (0,1)) = 0.9
         _Position ("World Position", Vector) = (0,0,0,0)
     }
     Category
     {
         Tags { "Queue" = "Transparent" }
         Blend SrcAlpha OneMinusSrcAlpha
         AlphaTest Greater .01
         ColorMask RGB
         Cull Off Lighting Off ZWrite Off Fog { Color (0,0,0,0) }
         
         SubShader 
         {
             Pass 
             {
                 CGPROGRAM
                 #pragma vertex vert
                 #pragma fragment frag
                 #include "UnityCG.cginc"
                 
                 sampler2D _MainTex;
                 float4 _Position;
                 float _Speed;
                 float _Height;
                 float _ParticleSpread;
                 float _ParticleSize;
                 float _ParticleSystemShape;
                 float _Cutoff;
                 float _Fader;
                 
                 struct v2f {
                     float4 pos : SV_POSITION;
                     float color : COLOR0;
                     float2 uv : TEXCOORD0;
                 };
                 
                 float4 _MainTex_ST;
                 
                 v2f vert (appdata_base v)
                 {
                     float t = frac(v.vertex.z + _Speed * _Time); 
                     float s = pow(t, _ParticleSystemShape);
                     float3 eyeVector = ObjSpaceViewDir( v.vertex );
                     float3 upVector = float3(0,1,0);
                     float3 sideVector = normalize(cross(eyeVector,upVector));
                     v2f o;
                     o.pos = v.vertex;
                     o.pos.x = _ParticleSpread * s * sin(62.0 * v.vertex.z);
                     o.pos.z = _ParticleSpread * s * cos(163.0 * v.vertex.z);
                     o.pos.y = _Height * t;
                     o.pos.xyz += _ParticleSize * (v.vertex.x * sideVector + v.vertex.y * upVector).xyz;
                     o.pos = mul (UNITY_MATRIX_VP, o.pos);
                     o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);
                     o.color = _Fader - t;
                     return o;
                 }
                 
                 float4 frag (v2f i) : COLOR
                 {
                     float4 texcol = tex2D(_MainTex, i.uv);
                     if(texcol.a < _Cutoff)
                     {
                         discard;
                     }
                     return i.color * texcol;
                 }
                 ENDCG
             }
         }
     }
 }

Any help would be appreciated