I believe your BOV spring is too strong. I've had an adjustable Greedy BOV before. If it's set too tight, it stutters. I think it's like this:
1. The pressure in the intake tract builds up as the throttle body closes.
2. The BOV opens.
3. The pressure is only partially relieved before the overstrong spring shuts the BOV again.
4. Pressure begins to build higher again.
5. Cycle starts over.
It's kinda harmonic.