Good morning Guys,
I am new to this site, I have a 2018 Gen 2 raptor, mine was doing the exact same thing, go out in the morning first start it would rattle for about 2-3 seconds, it is a noticeable rattle. Then it would quiten right down. No check engine light, ever, no power loss anything like that. Just the 2-3 second rattle. I am at 59k miles with mine, took it down to the dealer for the first time to do a 60k service. Luckily I took mine down now, I had 1k left on the original 60k powertrain warranty, so the dealer is going to cover the repairs under warranty, they said it is about a $3,000 dollar repair bill. I have been doing my own oil changes every 7500 miles, running motorcraft oil filter and mobil1 full synthetic 5w/30 from the beginning. I have attached a copy of the TSB which my dealership is saying is the issue. Mine is supposed to be ready for pickup tonight. They are saying it is a cam phaser issue. I will keep you guys updated on whether or not this fixes the issue. Also just so you guys know, if you look at the TSB it calls for over 9 hours of labor time and they have to remove the truck cab to do this repair, today will be a week they have had my truck. so it seems to be a pretty serious repair.