Help me with an under body rattle while idling!

[SBCT]

Thanks for reading. When my Yukon is idling with transmission in park, I have a pretty loud rattling noise coming from underneath. I rolled under there several times but can't pinpoint where its coming from!! If I put it in drive and give it a touch of gas with my foot still on the brake the rattle goes away, but comes right back when it goes back to idle. I'm thinking exhaust touching something somewhere but I can't find anything. Anyone experience this or have any ideas? Thanks

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---------- Post added at 11:36 AM ---------- Previous post was at 11:34 AM ----------

I should have added the sound appears to be coming from somewhere under where the 2nd row seats are. I checked out the muffler but didn't notice anything loose such as the heat shield and clearances look good.

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[ezdaar]

exhaust heat shields are notorious for rattle. grab some tools and get under there and tighten them up.

 

[JML07denali]

[emoji651]️[emoji651]️[emoji651]️ what he said.


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[Zed 71]

If it is not the heat shield, check the catalytic converter. Mine just went out and I had the same symptoms.

 

[scribble]

I've also had the ring on O2 sensors vibrating and making noise.

 

[GalaxyBlackEsky]

I ran into this problem as well but found out it was a bolt on my Cold Air Intake shield that was bolted to the body that was lose and rattling.

 

[undertaker]

I thought mine was the heat shield on the muffler, after some debating I just yanked it out and it was still there.

Turns out it was the baffles on my muffler that crapped the bed. Between the muffler and a leaking collector that turned into a snapped stud on a manifold, I now have american racing headers on the truck and they custom fabbed me a true dual stainless exhaust.

Hopefully its just the heat shield.