I just bought an 05 Supercrew with 140k but got a good price and when I test drive it it didn't make this noise then. It sounds like a ticking but I know it's not an exhaust leak bc it's all stock, it gets faster and kinda louder when I rev it up, I'm hoping to god it's not the cam phasers any input would be nice

 

maybe the headers

 

If I was a betting man it's the cam phaser(s). Similar thing happened with a 05 f150 I was going to purchase. Thanks to our mechanic's advise we returned it.

I did find this video helpful in telling me why the noise isn't there on startup but only after it's been running for a while
http://www.flatratetech.com/resources.html - search the page for phaser - 22 5.4 VCT Theory & Operation

Good luck.

 

Mine is on startup and while it's running, I know they are around 1400 to get fixed right?