Quote Originally Posted by JackCollo View Post
It doesn't lack on power when it is screeching. I took it to a mechanic and he says it's the turbo but to be honest with you I don't really wanna fork out 2500 or so for a new turbo I wanna try everything else first
Could it possibly be the turbo?

J/K

You say it's only started since you put the boost controller on it, how much extra boost are you flowing with the boost controller? You might be pushing your turbo beyond it's safe working limits.