Noise when I take off

2003 SLT envoy, I hear this rattling noise as i take off but it only happens when it gets cold outside.During warmer climate its ok. And it only happens on the initial take off as in at a light.stop sign.After the car warms up it goes away.What could it be?

Tough to diagnose noises in this environment, try getting it up in the air and look for loose or rattling exhaust shields, you need to at least determine front, center or rear of truck first.