Kinda of glad I found this thread (but maybe not!). I've had this issue for a while now and it drives me nuts. Issue is the 'tick' noise during a cold start and while under load with the engine cold. It will generally go away after about a minute or two. The noise is worse on cold days. Saw some of the posts and decided to investigate. Started the truck and got under it, sounds like its coming from the passenger header. Removed the manifold heat shield to look for soot and low and behold there was a broken stud and a fair amount of soot in the area. The truck is still under warranty and I'd like to take it in, however, now that I've been poking around under there I'm a bit concerned that they might try to blame the failure on me. I'm gonna call them up this week and see what they say about covering this, wish me luck!