it usually knocks around 3,000 and up when it does. it was originally tuned by intense just a mail tune then i had it custom tuned by a guy in minneasota. MAF is brand new as of february/march. front knock sensor is newer than that. The rear one is factory im assuming. this is why i hate iowa since there is really no one a around here to help me look at it. Would the downpipe have marks on it of the sway bar was hitting it?