Audio Problem

Hello i am having some problem with play specific audio sources, For some reason i cannot get them to play, I have tried a number of different things but just can’t crack it,

    public AudioSource tankEngine;
	public AudioSource tankTracks;
	public AudioSource tankIdle;

         void Start(){
		AudioSource[] audios = GetComponents<AudioSource>();
		tankEngine = audios[0];
		tankTracks = audios[1];
		tankIdle = audios[2];			

        void OnGUI(){
		if(CurrentSpeed > 0)
	              tankEngine.pitch = 0.5f + (CurrentSpeed / maxSpeed);


Everything else works like a charm but except it will not play,
If i remove “tankEngine.Play();” from the script then just enable Play On Awake on the GO Prefab’s AudioSource then it will work fine with the pitch acceleration etc.

I have been trying to get it to play from script so i can then stop the audio once stationary to play a idle audio clip. Any ideas? Thanks.

Edit 1: I am also starting to get a strange buzzing sound when audio is played Google dosn’t help, I am using the correct audio formats, In-fact i have tried every format of audio just to make sure

Never mind it was stupid of me, I forgot to check if audio was playing so the audio was playing from the start every update causing the buzzing sound, Fixed it by adding