Thin aluminum shields above muffler and motor pipes have deteriorated at the mounting screws and droped onto the muffler & motore pipe , it sounded like the the bottom of the car was shaking loose. when I checked there was 1 loose shield , that I pulled out, over the next 2 months 2 more fell down including the one above the muffler. these shields are not much thicker then aluminum foil. I gather it would cost big dollars to replace. This is the 2nd 4 runner I purchased new & is not as well made as the previous one I owned.