I have the Apexi twin chamber bov's that you have and I had the same problem. I fixed it by tightening the screw attached to the end of the bov. Mine would die every time I did a WOT pull or after a mild pull the idle would surge down as if trying to shut off and then come back to life. If its too lose you could experience this problem or if its too tight it could cause your turbos to get compressor surge (Did it to my 600's) so it has to be set just right where it doesn't cause surge or the idle to fluctuate. Hope this helps. Don't forget to let us know what fixed your issue