I have a tial wastegate with profec b. let say went I set it at 8 psi it will spike to 10-11 and the it will settle at 8psi. if I set it at 14, it will also spike up 2-3 psi to 16-17 psi and settle back to 14psi. Why is it doing that?

 

If you have an EBC, you should try lowering the gain. That is a very common cause of boost spike. Manifold--> downpipe design is another. If you have a source of obstruction or a resonance in your pipe you may have spike or boost "creep"

 

what manifold are you using?

 

what manifold do you have?if it is drag,it could be because the wastgate is on one runner.i just got my boost creep problems solved with a new manifold that let me feed the wastgate with all four cylinders.

 

I have the kooks manifold, I don't have this problem before, the boost was nice and steady....just recently. One thing I did is instead of using Ts for the vacuum lines, now every vacuums is plug into the intake manifold individually.