Chatter Noise

[WoodBoy]

I noticed yesterday a chatter noise that seems to be coming from under the hood around the driver's side. I can hear the noise when slightly accelerating. It makes the noise from about 1400rpm till about 1900rpm and i cant hear it anymore since the injector rattle drowns it out above that. It sounds similar to valves rattling when you lug an old 4 banger or etc. I can't really pin point the noise under the hood. Any suggestions?

 

[Whytry]

How many miles are on the truck?

 

[78f100]

It's most likely worn rocker arms. Usually you can hear it under light throttle but goes away on heavy throttle.

 

[Whytry]

What I was going say or lifters would be my guess