Here ya go for the plenum..
https://dodgeforum.com/forum/2nd-gen...um-thread.html

its the first stickied thread in the 2nd gen tech folder..

 

So I just watched this YouTube video...



Basically my truck pretty much sounds like that just not as loud. So I am now running off the assumptionn that is an exhaust leak. Given that with exception to the manifold, my whole exhaust system was replaced and the noise was still there I'm guessing its the manifold. Does this mean it is cracked? Whatever it is Is it worth putting money into it to fix it especially since in Alaska we dont have inspections? And also considering I plan on putting headers in in the future?

 

Also would an exhaust manifold leak explain why I also get code 0442 which is an evap code?

 

Evap is entirely separate from exhaust.

P0442 Evap Leak Monitor Medium Leak Detected

Might be as simple as a loose/bad gas cap. Generally though, as the trucks age, the 10 thousand miles of vacuum hose for the evap systems drys out, and cracks. Giving you a leak. (and it's usually back by the canister, which is under the passenger side of the cab on your truck, I think.)

Installing headers should fix your exhaust leak.