Our 2004.5 G35 has almost 49k miles, and it has no mods except for a Motordyne spacer. Last week, I drove it for the first time in a long time, and noticed a strange noise coming from the exhaust area. (My wife is the primary driver, and didn't notice the noise until I pointed it out.) Based on the video clip, what do you think the problem is?

<a href="http://s293.photobucket.com/albums/mm46/heftylefty58/g35/?action=view&current=VID00001.flv" target="_blank"><img src="http://i293.photobucket.com/albums/mm46/heftylefty58/g35/th_VID00001.jpg" border="0" alt="Photobucket" style="width: 160px;"></a>

I couldn't find anything loose, but doesn't it sound like the problem is inside the muffler? If not, I'll put the car up on stands and continue looking for something loose. Any thoughts/tips are greatly appreciated.

 

cant listen to the video clip at work but there may be a leak/hole in the exhaust piping.

 

I was wrong. The problem was really coming from a loose hanger. I actually lost the bolt at some point.

In this pic, the hanger is supposed to be vertical:



Another pic:



I've encircled the missing bolt in red:



Sorry about my ignorance, but does anyone know how I figure out the exact size of my missing bolt? Also, is the bolt something a general hardware store should carry, or will I need to go to an automotive parts store (or the dealership)?