2004 GMC Safari rattling noise under the van

Take Advantage of Existing Community Groups: Some communities have block associations, local community boards or other existing groups that may welcome a group devoted to noise problem. You may be able to attach your group to this existing organization which should allow you to use their already formalized stationery.

I have a 1995 van that has given me 2 different problems like this. Is your noise coming from just about the passenger door area under the van? Does it do it worse when the vehicle is cold? If this is your symptoms then it is the cone inside your Cataltic converter. I'm just letting mine rattle until I have $350 I don't know what to do with. If the noise is coming from more of the rear of the vehicle then there is a heat shield on mine that was held in by little plastic rivits that had broke and let it fall down and bounce off the tail pipe. I simply put a small #4 bolt in this to fix it.