I have a 2012 6.7l 137k mi on it, it has put in its work. Recently started losing power, the more I gave it fuel the slower it wud go. Then it went to knocking didn't sound like rod knocking, blew a big cloud of white an black smoke an started knocking more. I pulled the valve cover off found cylinders 4 an 6 rocker arms were not touching the push rods the bridge was Just laying in there next to the rocker 1 pushrod was bent ordered a pushrod an reinstalled it re torque everything an drove 1mile ran good just lacked power, then it went back to knocking, anyone had this problem ???? Is my cam shot ?? Can any1 help???????thanks ....