I know, this was discussed earlier, but I do not find the thread. I have this rattling noise just behind my neck (like a loose screw or bolt) but I don't find the source. Where to find and what to do?
Achim alias Waldemar
This is usually the rollover valve (6) in the fuel system rattling as its not well supported.

It can usually be silenced by using a plastic cable tie to hold it firmly against another pipe.