So, my Dad's 4.6 started making noise in the upper end. He thought is was a phasor, I was not so sure. We pulled the passenger side valve cover and found a failed rocker. The cam was fine, we just replaced the rocker and all is good.

 

How many miles on engine? I have a slight clicking some times. very hard to hear. Mainly on start up when cold.

 

Started noticing it just before 100k, was there hot or cold.

 

Mine started about 110,000 but can't hear it now. Might be nothing.
going to get an oil analysis and see if they can find any metal.