funny noise

I just bought my 2002 denali about four months ago and have sence noticed a funny noice. Hard to discribe but hopefully someone will know what i'm talking about. It sounds like a spring noise, mostly in lower mph.
Doesn't happen all the time, but when it does start it's very noticable. Any ideas?

can you be more specific

I just bought my 2002 denali about four months ago and have sence noticed a funny noice. Hard to discribe but hopefully someone will know what i'm talking about. It sounds like a spring noise, mostly in lower mph.
Doesn't happen all the time, but when it does start it's very noticable. Any ideas?

I have a 2004 Yukon. Had a noise like you are describing. Took it to the dealer they replaced the entire cluster (they thought that is what it was). Wrong. It has started again. I am not sure what to do next. If you discover what it is - please post. Thanks.

My '02 Yukon began making noise from underneath 2 weeks ago.
It finally bugged me so much, I braved the sub-zero temps to get under there - I found that if I banged on the passenger side catalytic convertor, I could recreate the noise.
Apparently the "guts" of the convertor broke apart and make very stange noises inside there.
Dealership $550 part + 150 labor
Aftermarket $299
I ordered it today.