If your truck has a ticking sound at cold startup and that sound goes away after minute or so....odds are you have a broken exhaust manifold bolt.

If so, and your under warranty take it in for repair as you dont want to do this yourself.

You can check easily as it is more often than not the rear most manifold bolts. When engine is cool crawl under truck behind front wheel...take a light and long screwdriver...tug on the tin heat shield and if its loose it's a broken manifold bolt or 2. They break off flush with head usually and removing them ain't fun.....I just did this repair as I didnt take it to dealer before warranty expired.

I went back with factory setup but if it happens again...I will be installing short tube headers.