I haw a 2010 F-150 FX4 (trim) 5.4 and it has made this rattling sound since the day I got it, and really diddnt think anything of it because the truck runs fine but I wanted to know what it was. It happens whenever you step on the gas just a little bit, and only in drive or reverse (that I know of.) It won't do it at idle or at any other speed. It generally occurs between 1-15 mph. It's not too terribly loud but you can hear it if you have the window open. You can also hear it of say you are going up a hill and to are canceling out the rollback with a little bit of gas.

 

My first question is are you still under warranty? I have seen the slip yoke in the rear two piece drive shaft cause issues at that you are having. There is a PCM and Tcm update that is supposed to solve it.

 

Mine does this too and I have no idea what it is

 

Cam Phasers... We all have the same problem with the 5.4...Only makes the noise when engine is warm as well. Search Cam Phasers on the forum, lotsa threads, some guys have had it for 200k and no issues just noise

 

Even the 2010's? Mine has 30k on it and the engine runs great, it just ticks at low rpms. I searched threads on here and people say its bad and others say its just noise....

I want to be sure this noise isnt going to ruin my engine.

 

It's normal if you maintained engine every 3 - 5k miles with a motor craft filter (has anti drain back valve that won't deteriorate like on some cheaper brand type filters i.e.). Also Seems the 5.4 cam phaser oil supply porting/holes are somewhat restrictive & vulnerable to sludge from people neglecting maintenance or even following fords 7500 mile oil change recommendation in owners manual but city driving . How do I know this .... my engine (stil with factory oil & filter installed) made the ticking noise one nasty morning when I had around 1500 miles on truck when it was brutal cold out then went away soon as the oil warmed , thinned out and could get to those phasers adequately - I bought my 2010 brand new with no miles & changed at every 5k , 10k & now at 15 k soon with no noise - it's normal 5.4 noise - relax

 

Ok, i will be sure to buy motocraft oil and filters for now on. I do my own oil changes so i keep an eye on things. My last oil change was with valvoline and a mobil 1 filter (i believe)