3.9 V6 Engine knock at startup

[TXd150]

I have a 2001 Dodge Ram 1500 WT with the 3.9 V6 engine. It has a noticeable knocking noise now at startup. It happens when the truck sits for a day or longer than that, after startup and oil gets circulated it stops. The engine is fairy new, just installed it last year. The engine does not have a warranty, I purchased it from a shop that had it sitting for a while due to a customer that didn’t pay. It was still in the plastic crate and had all the torque markings and such.I think it could be a rod bearing that’s bad, Is it possible to fix without taking the engine out?

 

[TXd150]

Update, changed the oil and added liquid Molly. Engine runs great with no knocking at startup anymore.