Do you have an O2 clamp? An O2 clamp will cure the stuttering during the vacuum to boost transition.

well im not running ne kind of emanage... can i still use the o2 clamp ?

btw, i noticed in your signature that u have a begi fmu also, are you running the stock fule pump ? how tight is your rising rate adjuster ? and are you running stock boost ?

yeah, you probably need an o2 clamp. you're ECU is trying to keep you at 14.7 AFR as you are trying to add fuel....it should be worse at half throttle cruising between boost and vac and noticable when stomping on WOT just as boost is made.

talk to Bruce (OlderGuy)

does that go for the idling problems at stop lights too ?