Exhaust issue 2002 Xterra developed a rattle. Looking under the truck, there appears to be a metal mesh basket type thing in the ehaust midbody. There is a ring that is loose around the pipe just after this mesh cylinder. Thoughts?

Most likely the heat shield has corroded off and is just sitting on top of the muffler or Catalytic converter. Regardless you can remove the shield and still run the the Xterra without any problems, the OEM muffler came with a heat shield as to the after market mufflers don't have one. The Catalytic converter also has a shield and you can remove it also as the Xterra has a heat shield on the floor board it self. Most exhaust shop if honest will tell you to just remove the rattling shield if there is no exhaust leaks or no Check engine light on that monitor's the Catalytic converter's performance.
A muffler shop if shady may advise you to replace the Catalytic converter and that can go for up to and beyond $400.00, so as long as there is no leaks or check engine light on. Go right ahead and remove the rattling shield.
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