Hesitating/Sputtering Under Full Boost

So like the title states under full boost I'm experiencing a bit of hesitation/sputtering. It starts in 3 through 6 gear at about 2800 rpm and continues all the way to redline. I took it to the dealer and was told it was probably the clutch however there were no "trans guys" in that particular day. I thought it could've maybe been a vacuum line or and electrical issue or something else. Im currently running a custom 91 octane unleashed tune with intake and exhaust and have been for the last two years with zero issues. Any input is appreciated. Thanks in advance.