If your research points you in the direction of the wastegate, then make sure is is good, that the rubber bladder (inside the actuator) is sealing (not ripped), that the wasgate control solenoid is functioning, and that all electronic signals are correct. I can't be specific on how to go about testing these parts, since in most cases the car actually has to build boost, which means that a load has to be put on the engine.
I wouldn't say that the lack of power is a problem with the turbo, just yet, if a tune up hasn't been done in a while, it may be a good idea to do that now.
I wouldn't say that the lack of power is a problem with the turbo, just yet, if a tune up hasn't been done in a while, it may be a good idea to do that now.