Engine knock/Clank

What is your question?

The engine is making a knocking sound at cold start up... If I rev it for a few seconds it goes away and will come back intermittently once its warmed up... I have replaced just about every bolt on part within the past year (Unrelated) Timing belt, tensioners, water pump, turbos, intercoolers, hoses, clutch, flywheel, ac compressor, starter, alternator, PS pump... I'm thinking it may be a cam tensioner what do you think?