My have a rattle coming from undernieth the front end / firewall area that you can feel in the floor bourds when traveling over slight bumps in the road. This has been driving me crazy for 2-3 years now. I have a friend with an 02 F250 powerstroke with the exact same rattle. Can anyone please help!

 

It could be a worn bushing. Check the shocks and sway bar.

 

also the drag link. I replaced that and my sway bar bushings and I am quiet as a mouse. Also check the torque on your u-bolts for the front leaf spings. Mine were only half spec and that caused alot of leaf movement. All three really tigntened up the front...lik a new truck.