Odd Engine Sounds, Please Help!

I have a 1996 Explorer XLT V8 awd and whenever i drive it lately it is making a sort of clicking sound from the right bank
if anyone can help me out with this it would be grand
the only things i can think of are the valve timing bieng off or that their is a small hole in the header.
thanks all

I have a '97 with the V8 and have the same problem. I have found the source of the noise; it is the tube that leads from the top of the right side exhaust manifold back up to the intake manifold. I believe it is part of the EGR system. I am not sure what you call that pipe. It has a section that looks like the bendable part of a flexible drinking straw. That is where mine is leaking. It is louder when the engine is cold, and it sounds almost normal when it is warmed up. I first thought the manifold was cracked until I found it. Anybody know how difficult this is to replace?