I am experiencing a clicking noise while at Idle, cant tell if it is doing it while driving, there is no change in performance.
Question could this be a Lifter Issue or something else. 2001 5.4 122,000 miles

 

There are several "Could Be" possibilities, but anyone that tries to diagnose over the net without actually seeing/hearing and checking for themselves, ALSO COULD BE MAKING A MISTAKE.
There is no substitute for hands on checking and guessing can be disappointing and expensive.
Consider finding a good shop with a good reputation and have them check it out.
A lot of unnecessary problems are due to improper or neglected maintenance. Could this possibly get into this picture?