So my truck has done this since new. Right now I have just over 6k miles on the clock and thought I would see if anyone else has this issue. I found some older threads of previous gen 5.0's knocking, but nothing on the 15-16.. My noise isn't really a "knock". It's more of a tick like a typewriter.. And it lasts about 15-20 seconds. This is at starts around 50 degrees. Doesn't do it once warmed up at all or throughout the day. Only on the very first start. My initial thought is maybe exhaust leak. I hate to take it to the dealer without an idea of what it might be just because I know how that will go. Leave it overnight, try to replicate it in the morning, then they say it's normal.. Which maybe it is... I'm not honestly that worried about it, I bought the 100k mile warranty, but still it's a brand new 45k dollar truck... Thoughts?

 

Sometimes a faulty anti drain back valve in the oil filter can cause a ticking at startup after sitting for a while.

 

Yeah that could be, I am getting an oil change soon.. maybe it will clear it up