I have a '05 F150 with the 3v 5.4. I noticed the engine has a light knocking sound. I thought it was the cam phasers, but the sound is there when the engine is cold and still does it above 1200rpm. The sound seems to be coming from the top of the engine and is more noticeable on the drivers side, about 2/3rds the way back. It is not the noise the injectors make because I can hear that tick also and it is independent of the other noise. And it isn't an exhaust leak. The knock doesn't get any louder as the engine speed increases, but does get a little faster. After around 1300-1400rpm the engine noise is loud enough that it drowns out the knocking sound. I had one mech tell me it's normal and not to worry about it unless it gets louder. Other than the noise the engine runs great.

The engine has 65k on it and the plugs were changed at 50k with MC plugs and i always change the oil every 3k with 5w20 MC and a MC oil filter.

 

did you ever get this figured out. my 06 sounds like yours and I't drives me crazy. I've only had it 2 months. didn't notice it when i was looking at it.

 

take a listen to the timing cover with scope. I have seem many of these motors have either timing chain tracks or tensioners worn out causing this kind of knock or tap sound.

Greg M.