The other day I was in second gear and hit the dual stage boost controller and at about 17psi the turbo started surging like it was hitting fuel cut-off. I shifted into third and it went up to 21psi no problem. So I experimented with all the gears the next day, nothing happened. Friday it was doing it again, this time however both second and third were doing it. Saturday, every gear was fine. What gives? Any suggestions? Is it my dual stage boost controller? My ecu? I wouldn't think that it could be my turbo because when I run 15psi it runs just fine, no surging at all. Any suggestions would help immensly.