I bought a 06 Navigator with slight roughness and 2 codes and dealership diagnosed cam timing skipped. Did some searching and reading and found out these have problems with cam phasers and VCT solenoids (sounds like a diesel idling) and/or guides wearing out and chain skipping a sprocket but still running albeit not as smooth nor powerful. The dealership said my phasers and solenoids are good at this point.
Anyone here have any issues or experience with these? I am planning on finding someone to do the chains, guides, tensioners, water and oil pump and see how that goes. Many just put in a new rebuilt long block but I like to see if this will cure the problem.

 

You tube is your friend. Lots of videos to review on this topic.
Here's a 4 part series that will help.

 

When the driver side cam phaser went bad on my '05 Navi the chain on that side jumped a tooth. When I replaced the phaser I still had a driver side phaser position error. OnceI found an app that could read actual camshaft position I saw exactly what the issue was. If I had the app before replacing the phaser I would have known to fix the cam position too. Two more tries I am still going strong with no issues.