What the heck is that noise and misfire (video in post)
 

My truck has run into a pretty serious issue. Right after hitting 200k miles of great reliability, out of the blue one morning she started running rough. I drove my 60 miles to work mostly fine just a harsh idle. Leaving work it was idling so rough it seemed as if she had a big ole cam in her ( or not firing on one :@) 30 miles later half way home she started making some horrible noise and losing power fast. Still haven't resolved it. Only rattled like that if I was going 60 mph up a hill 3-4 throttle in the past on occasion now it's whenever above 30 mph. I pulled the cat and that didn't fix anything.

I replace the cap wires rotor and plugs, as well as the coil. I just pulled the valve covers and the rocker arms seem fine as well.

Got the same issue. Just picked up my truck from an impound lot on a lien sale so no info on its history. Test drive seemed fine but then in my way home I got that loud ticking noise. No clue what it is. Did you ever figure it out?
It's on on throttle at 45+.