wont boost over 6 psi
 

My car all of a sudden wont boost over 6 psi & sounds like a Mac truck with aJake break if I try to go to 8 Psi. I was consistntly seeing 9 psi until today. i smy boost actuator bad? I searched and found "helper springs" how are the installed? one end to the rod? then where? or is my Mitsubishi Bov bad? Any help is apreciated. Joel