Hmm... Ok, so my car has been doing this for quite a while now... but my priority has been elsewhere for the last 6-8 months.

Anyhow... During hard acceleration (mostly in 3rd & 4th Gears) My boost will reach 21psi... but it kind of...
... pulses? Its hard to explain but it is NOT a smooth or consistant pull... its like it goes to 21psi... then drops to 18, then goes back up to 21psi, then back to 18.

I thought it was just a hole in a vacuum line or something that would only dump at higher pressure... but I cannot find a leak anywhere. Could this mean I should "Tune" my Diverter Valve? I'm still using the stock springs in my Forge D007 DV. I have the Tuning Springs and Shims...

Thoughts?

 

I assume you're chipped from the 21 psi.
Your DV does indeed need to be tuned for the engine tune.

 

Don't know that changing your Spring/Shims will help your problem.....but try the Green Spring with 2 Shims. I'm chipped, and that combo works best for me.