slight possibility that no one has mentioned, only from personal experience do i know this but when my tranny went bad, it started clicking, took off from a light everything shifted fine, put it in park at the house and could here it, went with engine speed, i swore it was coming from the exhaust manifold or y-pipe, drove to the shop next morning, as im turning in driveway clicking stops and truck slowly coasts into the shop, tranny had let go, if you cant figure it out and it really bothers you then have a shop look at it, just my .02

 

Lol I have always wondered what that ticking was after I got my pacesetter LT's, Now I know.

 

Andrew383 stopped by my place a couple days ago and I could tell he had headers right away. The noise is ubiquitous apparently.