As much complaining everyone does the 5.4L 3V is a good engine. The timing set is for sure the weak spot for it. Bottom end on these modular engines is very strong. While I appreciate an old 2 valve the 3 valve fixed a lot of things wrong with it. More power up high with the VCT and a more useable overall power band, improved head gaskets, intake manifold design, etc. The plugs certainly aren’t blowing out of the head like the older ones.......but they may also try to stay in there when you WANT them out lol. Although I must say I found the plug change to be easy. Best way to keep a 3 valve happy is change the oil & filter always and often. While not bulletproof it is a solid platform.
You're a 3rd gen owner, your word doesn't fly with us 2nd gen owners especially the 2005 owners, the 5.4 in its first design with no changes or tweaks is ABSOLUTELY A DISASTER, the timing failing so prematurely is ridiculous, the welded spark plugs are a nightmare of their own & the vct's stalling the motor on low revs is epic nonsense.
@JExpedition07 before you get all pissy I challenge you to go buy a 2005-2006 expedition with it's original spark plugs and timing set and drive it for 12k-15k miles in 12 months or less then come back her and "brag" about how much better these 3v engine are.... matter of fact I bet you by mile mark 7982 ater you buy it you'd have already set it on fire while it's being crushed at the scrap yard...