May be beating a dead horse, but my 2005 G.T. has a rattle in the rear trunk area from hell. Took the spare out and all assorted hardware; still rattles. Not the Shaker 1000 woofers; it's seemingly on the driver's side. Sounds like metal on metal, but all the welds I can see with the trunk trim out are tight. Sort of resonates with the exhaust, but my Flowmasters and other pipes are tight too. HELP! I've had this car about three weeks and it only has 11,000 miles on it, so I'm going crazy. My wife's '06 doesn't suffer from this, and neither did the '06 I traded in.

 

Are you sure it's not the Flowmasters themselves? They were notorious for having broken welds internally that vibrated bad over time.

 

Well, I thought it might be, because I've heard the same thing. These Flows are weld in 40 series with stock tips and I tapped and banged them pretty hard with my fist, and they didn't SOUND busted.

 

I had a rattle... it was the cover on the back of the trunk that hides the hardware and lighting Had to redo the clips, problem solved.

The mirror, though... haven't delved into that one yet.

 

Already tried that one too. That cover is completely out of the car now, thanks to me tugging a little too hard and breaking it. Still got a rattle and sounds more and more like the left quarter area.

 

I get rattles from my pass quarter area. If I touch any of the panels on that side it goes away though.

 

This is a tinny, metallic rattle. Aggravating as hell. Definitely metal on metal. I'm about ready to go back to the stock mufflers.

 

Check the rear hanger rod on the muffler itself, sometimes they're too long and can contact the metal bumper under the car.

 

You don't have aftermarket LCAs do you?

 

Mymirror rattled. I popped that ****** off and tightened the screws behind it. \

 

jump in the trunk and have someone take you for a ride.

 

+1 I remember Tocobill had to cut some rod on his because they were to long.

 

license plate?

 

Jumping in the trunk sounds like the best option so far. Thought of the license plate too, but it's tight with four screws. More in the left quarter area. Really heard it tonight good. Twelve year old kid in the back with us told me it's coming from that area too. Nobody at the dealership I work at is really enthused about finding it either. Guess I don't blame them.

 

One thing I did to mine was to grab all the "christmas tree" push retainers under the parcel shelf, in the trunk, with a pair of pliers. I gave each a little tug to see if I could get one more barb to grip a little better. There was one to the left of the left rear speaker that was quite loose.

I also pushed in on the two retainers, near the floor, just under the front of the rear seat lower cushion. They were quite loose.

 

I had a similar rattle that drove me up the wall. I could not figure it out. When I checked the rear most exhaust hanger rods, they didn't touch any part of the the bumper frame...but they were close. I eventually figured out that when the exhaust was cold there was not contact, but when it warmed up and everything expanded a bit, it was just enough to bring the hanger rod into contact with the frame. I cut off about 3/4" of the hanger rod and the problem was gone finally. These were aftermarket mufflers as well.
Good luck in getting the problem solved, I know exactly what you are going through.

 

I solved it; I put the stock exhaust back on and said the HELL with it! The last poster may be on the right track though. The guy who put the Flows on for me said the brackets were welded on wrong. They are weld in Flows, not an axleback. He rewelded them, and could have screwed it up I guess. Now I need to do something with these mufflers. Good mufflers, 40 series with offset inlet/outlet. Just need to get someone who knows what he's doing to put on hangar brackets or they're good to use in another application.