I would start with the basics. Plugs/Coils/ETC. Perhaps a coupler getting loose or some boost line cracking. Check the rear of the CAP and make sure it's sitting well, check the intercooler for leaking. The list goes on but there's a start my friend.Started happening last week.. With minor acceleration, with boost at about 5 psi, I will see boost go up and down from 3 to 5 very quickly..like bouncing.. And I can hear the engine sound do something similar.. Any idea what it could be?