I mentioned a clicking noise earlier... Well, after poking around in the engine, the noise is NOT coming from the accesories, it's coming from right under the intake manifold. Any ideas what it could be? Lifters? Basically it's a very fast clicking from inside the engine, present at idle and while revving.

 

fuel injectors

 

Possibly... I'll run some cleaner and let you know... Any other ideas? Is there a way to test and see if it's the lifters?

 

What did you found out what's really wrong with it? because my truck making same noise today.

 

exhaust leak?