Originally Posted by low_&_loud
This is similar but mine is definitely a higher frequency. Ill try to take a video as well when I can, probably should have done it to begin with. Mine is also occurring with no change in throttle position, i.e. if I'm barely on the gas cruising in 5th, and ease into 1/4-1/2 throttle and stay there, it'll build boost and begin to accelerate then start the chatter after a few seconds. Yours seems to be when you accelerate then back off the throttle a bit?
mine will sometimes do it when i back off the throttle. Sometimes when driving up hills though I can be holding it perfectly steady and then all of a sudden boost drops off completly and the whole car will shake.
My tuner thinks that my bpv might be faulty causing the fluctuations.