I've been hearing a lot of talk about these going bad and causing all sorts of unpleasant problems. Before I pull mine and replace it what can I do to ensure it is in fact defective?

 

Unplug them. It will most likely throw a check engine light but will not mechanically affect the engine. I ran mine for for about 4 days until my new ones came in. I had chatter coming from my 5.4 and it went away when I unplugged the VCT solenoids.

 

I just changed a set in my brother in laws truck Yesterday

 

if it is an earlier model 5.4, i.e. 04 thru 06 then the difference is the orifice at the bottom and the general design, as well as a check ball added if I remember correctly. Whether they fail or not replacing them can extend the life of the phasers as the larger orifice allows more oil flow and the check ball keeps them from running dry.

 

I have an 05 with the 5.4l. My reasoning for wanting to replace this is because when Idling at a red light my truck shakes vigorously from time to time.. I know this part in particular causes a lot of headache when it fails. I've watched a video or two to familiarize myself with the process. From what I understand the driver side valve cover is where the solenoid is located. Do I absolutely have to pull the valve cover to replace this part? If so, where can I find an accurate set of specs for the 15 bolt mess I'll have to deal with?

 

05's solenoids are in the valve cover not under like later models. Here is a write up I did in April 2015, with photos.
https://www.f150forum.com/f4/vct-sol...cement-298402/