control solenoid valve should have some noise because its working on various frequency current. Simply, its closing and opening all the time. Changing frequency will change open and close time of the valve and that is how it controls position on waste gate rod.
solenoid is problem in rare cases, but
pressure sensor is most likely the problem. You just need to pull it of the
pipe, clean pipe and sensor, plug it back to pipe and tie it to pipe with some wire plastic.