So I recently posted a thread regarding BOV flutter, but I think this is NOT what I have. Anyway, I'm currently running stock turbo with IX DV, GM solenoid, catback exhaust, intake, and that's about it. I've noticed that in 2nd-3rd gear, hitting full boost I make 1.6 bar or so, and taper from there. In 4th and 5th, however, it hits 1.7-1.8. Also, it makes a "fluttering" sound under full boost and the boost needle jiggles slightly (like 0.1bar, not much). I don't feel anything as far as driveability. But I'm wondering, what is this? And why only in high gears?