When ever I really get down on my truck, like getting on free-way, I hear a faint rattle like it is by the firewall. Could this be the rocker arms needing to be adjusted? Or is theree something else that does not show up in the search function?

 

I would look at the exhaust pipe from turbo. If it is close to the frame or body, the extra torque could cause it to touch and cause the noise.

 

Hopefully that is not the problem, but I will check when I get off today. I have Rip's 4" turbo back back exhaust.