I have a 2000 Chevy Blazer, that has a metal clanging noise under the front part of the car (this has nothing to do with the wheels or suspension). I notice it the most when I have moved the gears out of park or am sitting idle somewhere. At first my husband thought it was the tail pipe but looked and it wasnt. He ck'd the motor mount which seems to be ok.. My ck engine light has come on with the code ofP0420, not sure if this is related to theclanging or not. Husband says it may be the catalytic converter?... We need help.

Thanks!
Dee Dee

 

I can't say for sure, but I had the same problem with my wife's 97 Astro van. Although the check engine light never came on. When you first start it, it would make the noise you describe. As it warmed up the noise would go away. At first anyway, then the rattling would'nt go away. It did turn out to be the Catalytic converter. If I pounded on the converter it made the noise. Replaced it, and the noise was gone.

Good luck.

 

If it makes a clang when you put it in gear it is probably a universal joint, a cheap part.
Try puting it in drive then reverse a couple times slowly with the brake on and engine runningto see if it makes the noise.