In Reply to: F150 clatter/new wrinkle posted by lonestarjeff on December 05, 2018 at 22:53:25:
Condensation increases in colder weather and seems to be cleaning out your exhaust system as we move into winter. This seems to be more evident in a truck that is not driven every day. One thing that this does bring to mind is carbon buildup. I have heard of a piece of carbon buildup breaking off and hitting a valve causing some chatter. It eventually burns up, or some folks do the SeaFoam thing.
A timing chain redo would be a good bet if you have over 200k. Good