Originally Posted by
Karlos G
The bleed valve is not causing your lack of boost!
If it will not hold anymore then it's either the turbo, actuator, the cam has shit itself, or your timing is being retarded!
Sounds to me like the turbo doesnt have the legs (although 12psi is very low on a stock enigne), or the timing mate.
if the spring is at it's limit though, the extra pressure in the exhaust housing will blow the wastegate open a little, causing the boost to drop off a bit.