Too much tension could be causing your surging. Hook up a boost leak tester to it, and disconnect your recirculation. You should be able to hear whether or not its leaking. Just make sure you open your throttle body, because your source for the BOV should be from the manifold. Do you have a good boost source that is not shared by a boost controller or other device? Do you have a boost leak tester? If you own a DSM and don't have a boost leak tester, you're going to wish that you did.