Hi, im new to this forum and to f150's. I just recently purchased a 2008 F150 Fx4 Scab 5.4l with 31500 miles on it after trading in my 2008 Silverado Z71. I just got it a little over a month ago and have been hearing the knock and just thought it was what the motor sounded like until i came on here and read about the cam phaser problems these 5.4l tritons are having. So i took a video of the motor running fully warm to show you guys and if you could tell me if indeed i have this problem so i can take it to my dealer and get this solved before my warranty is up in a few months. It also makes the noise when cold. The truck now has around 32300 miles on it. Any info would be greatly appreciated since im new to the ford world due to driving chevy trucks my whole life. http://www.youtube.com/watch?v=3NvSRAhj0Ag

 

It would seem that you do have this condition.
Take it back ASAP or sooner and make sure the service manager sees the same thing...get it handled under your warranty. Could NOT hurt to voice your frustration/dissatisfaction to customer services at Ford Corporate office too. Your truck has WAY too low of miles to sound like that.