I have a 2000 Silverado 2500 with the 6.0. When the truck sits at an idle, it shakes. The shaking gets worse, the warmer the truck gets. It feels as if it has a misfire, but doesn't. The check engine light never comes on for a scanner to pick it up, and luckily it never stalls. The shaking is also accompanied by a loss of power, but i'm unaware if the two are relative to each other. I have had multiple combinations of plugs and wires trying to solve the problem, with no relief. Anyone with input?

sounds like a broken mount, power loss is becasue of freedom of the engine, check the rubber in the mount

Pop the hood and power brake it, have sombody watch it if possible also check to make sure you don't have bosh spark plugs, same thing kinda on a mustang today at work bosh plugs present switched w/delco solved it never set of c/e light for misfire, wierd...

i would also check all of the mounts...