Just bought a 2005 f150 with the 4.6 in it. It started having a ugly knocking noise almost like a diesel when I crank it over then starts again once it warms up so I parked it. Checked it out some more today still makes the same noise and it is now dropping the oil pressure all the way down and comes back to the middle non stop. Any ideas what it might be? I was told it was the camshaft phaser but what do you guys think?

 

You sure it's a 4.6? Only the 5.4 3 valve has cam phasers.

 

I am pretty sure. I checked the vin and it’s a 4.6. Unless they swapped it but I’m not sure if there compatible?? Any ideas what it might be? I’m kinda regretting buying the truck now. Something about it being a step side extended makes it really attractive to me.......

 

I recommend you get a knowledgeable mechanic to listen to the engine knock to determine what it is. If it is in the valve train, you need to start removing valve covers to check it out and not drive it until it is repaired.