2005 legacy gt Loud rattling noise when I let of the gas need help asap

My 05 legacy gt has been having a pretty loud rattling noise when I let off the gas I haven't found any metal in oil or pan and it has a brand new turbo but the noise seems to be coming from back near the turbo it is driving me crazy I need help ASAP

Why does it have a new turbo? What kind of turbo, and where did you get it? What mods & tune do you have? How long have you had the car, and what other history can you tell? Can you post a video?

Check that all heat shields are tied on properly. That's one of the most common sources for that kind of issue.

 

It can also be the cat that's starting to fall apart.

 

Neither is fatal, but you may need a new cat.

Hi. Did you ever figure out the cause for this? I am having the exact same symptoms.

Heat shields vibration is common. When it has been really loud, a bolt is significantly loose. However, I experience this rattling often when letting off the clutch. It is especially noticeable with the warmer weather and driving with the window open. When driving by a retaining wall, I can really hear it.

 

I think some of it is just the thin heat shield material and the resonant frequency matching vibration during clutch in. I just put in new clutch, Group N engine and transmission mounts. The base level of vibration and NVH is noticeably higher when clutching in.