2004 Ford pickup 5.4 liter motor tick noise

My previous truck was an 05 F250 with the 5.4 and yes, it did have the ticking noise after 100k spark plug change. I was just told to ignore it (which is hard to do after owning an engine in a previous vehicle that threw a rod). Traded it in 34k later. Never did find out what it was, but on mine it didn't seem to affect the performance of the engine. From the sound of these other posts, I probably should've investigated it further.