The problem with the cam phasers is the locking pin. At idle the pin is engaged, the oil PSI pushes on the pin to disengage. As time goes on the pin gets worn and will not lock. Also it is a fact that cheep oil filters do come apart and block VCT, this includes ford oil filters. Ford recommended synthetic oil.
I have a 5.4 POS I just pulled apart, cams pitted and scored also cam caps.
What a wonderful feat of engineering no bearings in head. Got into timing cover tensioner plunger collapsed. This causes oil to **** out of the tensioner and starves top end. I knew the truck need timing chain buy the noise, but when pulling the rocker covers off and seen damage just could not believe it.
Thats why there is such a shortage of used engines and the wreckers want 3,000 grand for anything under 100,000. Ford has know about this problem for years, that's why they want over 2,000 grand per head. So in closing they design this POS then jamb the customer for the part.