so today while I was ideling I got a strange rattle that was relatively loud and it seemed like maybe part of the exhaust was ratteling on a heat sheild or some of the nuts and bolts may have been loose. Then the rattle went away and stayed away for a while. Then it came back again on idle. So I checked all of the connections and everything seems to be tight on the exhaust. The rattle only occurs on a very low idle, really lower than it typically is, maybe 500 - 700 rpm, more in the 500 - 600 rpm range. Which is low, typically it hangs out between 800 - 1000 rpm at idle where there is no loud rattle.

Today is the first time this has happened so let me give some specs on the conditions today:
high: 42 deg F
High wind, excessive rain

What's on my car 06 6sp MT:
CT icebox, CT header, CT cat back, CT RSB, Neuspeed FSTB, TB bypass, RT cat, RT cat hardware kit.

Does anyone have an idea what would cause the rattle (other than the typical CT header reply, header has been on for months and no rattle), or what could cause the unusually low idle?? Thanks!

 

loose flange?
maybe loose hanger?