It's was poorly done, the actual mechanic is looking at it now. The boy he had work on it before has been fired. Heck I was planning on doing the work myself but not when its -20 in my garage its a little difficult to hold a wrench. But as far as the knock no I didn't hear anything like that. I thought maybe I burnt a cylinder with it running lean but not to sure. Gonna go talk to my mechanic today and see what's up though.