No one around here locally can seem to figure out
what this issue is but here's the deal with my FD:

(1) My car boosts nicely from a dead start or from low speeds/gears.

(2) At times, especially on the highway, if I am crusing at 3,500-4,500 rpm for instance in 4th gear and go WOT to pass , I get 0-3psi boost and some increased rpms only. When I let off the accelerator I hear the "bhew" sound (boost leak or blow off valve??)

It doesn't always do this. Usually just when I've been cruising. Around town I get good boost although I've noticed now that I really don't have a boost transition pattern or it happens damn quick.

I have stock sequentials, Profec B Boost Controller, PowerFC, Pettit Large SMIC. The last guy said he removed the PowerFC from boost control and set up the Profec B as he would "an Apexi". Not sure enough what all he meant by that but it still does the same thing (except now my Profec B actually controls boost whereas before I was forced to use the PFC)

Any ideas?

David