Odd sound when accelerating

[Chad Wilson]

I am trying to identify a sound coming from my 2001 Silverado. Best way to describe it is the sound a bike wheel makes when you stick a playing card in the spokes. It is kind of a ticking sound that only occurs when I am accelerating from a stop. It stops when I hit about 30 mph and it also stops as soon as I take my foot off the gas. I assume it is a part that only rotates when pressing the accelerator? Any ideas? Thanks

[Mikebtte]

Could be an exhaust leak. 

[rjgti]

inner cv joint