Ok, so I've been working on the torque section of my spark map. I have pretty well set up the way I like it. Car pulls nice, hard, and smooth. NO knock on accell in any gear. However, tonight I got nock during decel after an accell to about 5K, let off the gas and got knock. Any Ideas of what to look at?

Thanks

 

Clutch chatter?

 

That's what it appears to be. It has only happened the one time.