Rattling on cold starts

Mine turned out to be rusted loose heat shield on catalytic converter. Start the truck cold and it has a little more vibration to it then when it warms up and idles down the sound would go away. Couple new bolts and lock nuts and she’s good as new.

 

I've been having the same issue. I called Toyota and just get a quote on a timing tensioner replacement along with a water pump. I was quoted at $5500. But they also said they've never heard a tensioner make this kind of noise that I described to them. So they suggested that I bring my truck in overnight so they can replicate the noise. I haven't had time to do this so in the mean time i've been simply starting the truck and hitting the road instead of letting it warm up for a couple minutes. It makes me nervous hearing the noise and not sure if its one of those things I just bite the bullet or if I can get away with it for another year.

 

The rattling you describe sounds like your cam tensioner(s), try an oil change with 5W-30 instead fo the 0w-20.