So I just bought a 2006 f150 lariat with the 5.4 triton. I bought it off a used lot being told it was nothing unusual for the triton engines. Nope. The clicking noise is comming from the drivers side. It can not be heard looking over the top of the engine with the hood up. It can only be heard through the driver side wheel well and under the truck. What is really weird about it is it's loudest under the truck. If it's a cam phaser why is the sound loudest from the opposite end of the engine and can't be heard from the top where the phaser is located? It sounds like the noise is the camshaft hitting the rocker arms or whatever they are called in SOHC engines. I dont know what it is. I can't stand that noise. That **** is like nails on a chalkboard to me. I am scared to work on it myself so I wanna have other input before I take it to shop. I'm not taking it to the ford dealer. You could get better service in a graveyard. Any input would be great. Feel free to ask further questions.