Ok so I have been having this problem for awhile now. It seemed to have gotten better over the winter. But now that its getting nicer its back. My car seems to almost studder/hesitate and my exhaust note almost sounds like its misfiring very mildly. Almost more of a gurggling tone. Always at lower RPMs right before I go into boost. Around 10 vac. I am thinking its my mafs. I do have it relocated. And I do have a k&n filter. I know they have oil in them and it may have been coated. I havent herad of any1 having mafs problems do to relocating but maybe I missed it. No cel right now. Please if you have any ideas post them. I am getting a little frustrated.