thats the question guys. i have friends with both 4.5s and 06s and there trucks are louder as in injector rattle than mine. kinda like a chik-it chik-it chik-it sound my 05 is quieter than a mouse fart? are the injectors different on these years? and a side note to this question is that this is BY FAR the best automobile let alone truck ive ever owned. my 02 with stage 2 injectors and boost fooler was awesome, but this 05 pulls my same trailer just as fast up the same hills, and is more rigid, better brakes.... man i could go on and on.

 

maybe your truck is worked harder than theirs.