Looking for some insight please. My 1.8t AUM has been pretty poor on boost these past couple of weeks. I ran the vagcom and it came up with the "17956" code - N75. I have replaced with a new valve and the problems are no different. If the code is pointing to the N75 valve and I have replaced that, what can the cause be for throwing up the same code? The boosing issues are pretty constant, but there are spells when the response is good and the car seems to behave.
Most times under acceleration the boost is there to start, but very quickly dies abruptly. I am looking into doing a boost pressure test, but need some pointers to make sure I am going down the right path.
Any thoughts?