I have a2000 silverado 1500 4.3 V6. When my truck is idleing, it makes a loud rattling noise. We checked the flywheel, and there is no cracks, and its not loose. any ideas of what it might be?

 

I have a 1500HD 4x4 with a 6.0L and when you first start it, it rattles. I have decided it might be a light metal heat shield or something that rattles until it warms up. I need to get under my truck when I start it and start investigating.

 

i have a 2000 silverado, and sometimes it would rattle...turns out it was the exhausts heat shield right above the back of the cab hitting the body. i just bent it with my hand the other way and it has been fine ever since.