ok so i have a 2004 f150 v8 4.6l. every time i come to a complete stop at a light or stop sign ect...my truck makes a rattling noise, sounds like something might be loose but not sure. but if i put it neutral or park it stops. so i cant really find out where its coming from cause i just cant get off while its in drive of course.can it be some thing with my headers? if you have any idea what it might be please let me know, anything info would help thanks

 

get someone to sit in the truck when its in drive then you can climb under and have a look,i'm thinking it could be one of your heat shields for your exhaust.

 

thanks for the info, i thought it might have been the cats but ill check it out thanks