I've had my truck a year this month and ever since it was new with 2 miles on it I have had this engine knock at cold start. Basically truck sits over night, get in it in the morning to start. Engine roars to life and settles after a 1-2 minute warm up and then once RPM's settle to the normal 650 range it's clang, clang, clang...clang, clang. I've done some quick research on the Coyote motor regarding the noise, almost nothing comes up with F-150's but there are countless engine knocking, or piston slap sounds coming from Mustang Coyote V8 owners.

The sound is similar to tapping an empty glass with a spoon very lightly, and the sound seems in rhythm with the valve train and not the flywheel if that makes sense (I'm no mechanic) If I rev the engine or bring it up past say 1000-2000 RPM it goes away but comes back once the RPM settles back to 650.

Here is the kicker, drive the truck for more than 5 miles, or enough to really warm everything up and the motor is whisper quiet. I was thinking it's piston slap, as I had an '08 GM 3/4 with the 6.0L gas motor, an engine know to have piston slap as part of the design and that is similar to what my engine sounds like. The only thing is my F-150's knock is gone after the truck is fully warmed and doesn't come back until the truck has sat cold for an etended period of time or overnight.

It doesn't really bother me as 98% of the time I just get in the truck, let it idle till coolant comes up to at least 111 degrees and then drive off so I never really hear it. My Chevy's 6.0L Vortec would just knock all the time no matter if cold or warm Lol.

Truck is a 2011, 5.0L with 16,000 miles YTD.

 

did you have the idler pully whatsitshoosey done cant remember the actual tsb number ill lokk mine up later