Engine knock when cold

Hello,
have a 1999 Dakota sport with the 4cyl 2.5 eng and has 88k miles. When I start the engine there is a knock and after about 3-5 min it goes away. Some one said that it could piston slap and I need to check the rod/main bearings. I thought is was a leaky lifter. I also heard mention of a wrist pin. How can I narrow this down?

Thanks!
Alan