Hi after some advice on a possible faulty dump valve. I've got a forge dump valve fitted its been ok up till a week ago, when i back off the accelerater the dump valve now seems to make a different pitch noise then a sort of vibrating noise, but i've also developed a whistling noise when putting my foot down a bit can anyone help me please.

 

the spring inside snapped on mine once. got a new one from local car mod shop for about £5. its easy to take apart .