Video with air cleaner box open so you can hear. Been doing this for a month. 15% loss on all rpms. New plugs, cap, rotor
Check engine light flash shows no codes, Valve lash is in spec. New engnbldr.com head 2 years ago. Catalytic converter removed years ago. Carb cleaner test done on all intake. Airflow Sensor turns easily, not dragging. Could it be a potato stuck in my exhaust ?

Video;

Air delivery is stock (no cracks)
Valves, chain & guides are 2 years old and inspected with lash check
New chain tensioner hasn't been touched in 2 years - it's been running fine

 

Is your air intake system stock?

Have you checked the air boot to the throttle body for cracks?

 

Doesn't sound good at all. Lots of high frequency noises, metal on metal type. Oh boy.
Take off all accessories

Probably a valve?

 

Engine sounds like it is misfiring to me. The cause I don't know.

 

Op has enough info in the op, but I got nothing.
Need more information please

Maybe a vid standing in front of the truck, reving it at the throttle body?

Test all sensors. A quick roger brown google search will get you there.

Recheck timing.

 

I'll throw out chain tensioner. Did you replace?
The proper torque for it is something very low like "tighten by hand / loctite".
If it's too tight it gets stuck in the open position.

Is that the chain I hear?