I have a low boost problem and discovered each valve has a different part number. I replaced the one by the turbo a few years ago and it seemed to run a little better but not like it used to. Come to find out it looks like i replaced it, with the one that goes at the front of the engine. Im going to replace it with the other part number. The valves look identical but a note on eeuroparts says one cant be interchanged with the other. Im gonna give it a try.