Q: Cam phaser symptoms? 2006 Ford F-150

Noise and/or failure of the variable cam timing phasers is a well known issue on the 5.4L V-8. In 2006, Ford issued a technical service bulletin, denoted TSB 06-19-8, to explain the service and repair procedures to deal with the noise.

Typically, worn phasers create a loud and rough idle. Often, a knocking noise is heard. In some instances, the noise is not due to wear in the phasers but rather low oil pressure due to cam bearing wear in the cylinder heads. If that is the case, the heads may need to be replaced or machined.

See the TSB for specific instructions but additional reported fixes have included installing a high volume oil pump. That has has the effect of increasing oil flow to the cam phasers. Some owners have also tried locking the phasers at base timing via installation of plugs that prevent the vanes from moving but this is not recommended as it defeats the VVT capability and the PCM would have to be custom re-programmed.