Exhaust problem?

I have a 1990 Lumina 3.1 that sometimes will sound like it has an exhaust problem. It always happens when starting the engine when it's cold. Once started, it idles the same but sounds like there's a large hole somewhere. Then after about 2-3 minutes of running it sounds fine. It has been around 25 degrees with snow, and I was thinking maybe snow or ice was lodged somewhere then eventually melts (I don't know just a guess). Note, this has only happened twice. If you have any ideas, i'm open for suggestions, Thank you.

Lotta times a cracked or loose exhaust manifold will leak real bad and be noisy when cold, then as the metal expands the leak closes up somewhat, and it quiets down.


But it wouldn't come and go, I'm not sure what you've got...

Lotta times a cracked or loose exhaust manifold will leak real bad and be noisy when cold, then as the metal expands the leak closes up somewhat, and it quiets down.


But it wouldn't come and go, I'm not sure what you've got...


Yeah I was thinking that, but it was just bizar how it only did it twice
Thanks for the input.

Just a Though..............

My Lumina had a bad exhaust rattle/tickin'/knockin' noise when I first started the car for about 2-3 minutes. It just seemed to me the exhaust sounded louder too, but maybe it was just my imagination trying to figure it out. I would look under the car and feel around the exhuast pipe for leaks but never found anything. Finally it bugged me enough to check some more. I discovered the the Catalytic Converter "innards" had come loose and was rattling bad when the engine was warming up at a high idle. It was just the right RPM to really cause it to get noisy. It would fade out at an idle and most other RPMs. I just kinda kicked on the Cat Conv with the engine off and I could here the "innards" klunking around. The outside of it and the rest of the pipe were all intact so I just didn't notice earlier.