Fade In And Out (GUIText)

So, I look up in here and then I try to fade in and out by making this

 function Start () {
     yield Fade.use.Alpha(guiText.material, 0.0, 1.0, 4.0, EaseType.In);
     yield WaitForSeconds(2);
     yield Fade.use.Alpha(guiText.material, 1.0, 0.0, 4.0, EaseType.Out);
 }

I attach to my all GUIText that I wanted to fade in and out. I set up everything here in this script

 var Part1per1 : GUIText;
 var Part1per2 : GUIText;
 var Part1per3 : GUIText;
 var Part1per4 : GUIText;
 var Part2per1 : GUIText;
 var Part2per2 : GUIText;
 var Part2per3 : GUIText;
 var Part2per4 : GUIText;
 
 function Start()
 {
     Part1per1.enabled = true;
     Part1per2.enabled = true;
     Part1per3.enabled = true;
     Part1per4.enabled = true;
     Part2per1.enabled = false;
     Part2per2.enabled = false;
     Part2per3.enabled = false;
     Part2per4.enabled = false;
     yield WaitForSeconds(11);
     Part1per1.enabled = false;
     Part1per2.enabled = false;
     Part1per3.enabled = false;
     Part1per4.enabled = false;
     Part2per1.enabled = true;
     Part2per2.enabled = true;
     Part2per3.enabled = true;
     Part2per4.enabled = true;
 }

For Part 1 it's working fine but when it reached Part 2 it doesn't do anything. It's fade out forever and can't be use for multiple times!

So is there any better way to fade in and out GUIText?