Ok, I've had this problem for a bit of time now but due to work and other issues I never really got to solve it.

Here's what I found out though.

My boost pattern is 5-8-13

Its probably hitting 13 from boost spike as my car is still sequential.

What can cause the primary boost to be venting like that? I mean, once it hits about 4500 rpms it rises to 8 really fast and hits 13 then slowly back down to 10.

What is making the primary lose boost until it hits the transition point?

I don't think its the Y-Pipe, Intercooler Piping because if I understand this correctly, if any other the pipes were loose, I would lose boost all around and not just the primary.

Where else should I look?

 

How consistent is it? All the time, or just once in a while (like after a hard run)?