I put together an overview on why I replaced my 2004 F150's 5.4 3V's VCT solenoids with a revised Motorcraft part.
Please note that if your truck does not have the large seals, then you MUST pull the valve covers to replace the solenoids.
Link to the Solenoids and seals for the trucks with valve cover access:
https://amzn.to/3aenfl6