My 03 WRX has started acting weird. The car is completely stock besides a turboback. problem is that I have an intermittent power loss when the car starts boosting with the accelerator pedal pressed all the way... I can feel the turbo kicking immediately at around 3600rpm with great acceleration, then at 3800rpm the power decreases a bit (still holding the accelerator all the way down), then at 4000rpm kicks strong again... and at 4200 another power loss until 4300rpms when it kicks again and so on... this happens always at full boost and in any gear... 61k miles, no misfires, no cel.
Any ideas? Thanks