Inner Fender Wells
 

I have a 2007 4Runner and am having either rattling or thumping noise coming from the fender well covers. Is there a fix for this ? I've tried everything I can think of to stop it, but to no avail. They seem to be lose and the plugs or pins don't seem to want to tighthen. This happens more when I'm on the Interstae than in-town driving. Any help will be appreciated.