Start with some higher octane by either using Xylene or GT100 to see if knock goes away. Do you have EVERYTHING for ignition up to par ie: spark plugs, wires, coil, etc. How about adjustable fuel reg, etc? (Ok see you got the afpr)
I need new Ignition wires, still have the originals. THough, they seem to be in very good shape.
I think that will be the next thing I replace.
Oh, and Running Xylene, which I have, is not an acceptable cure. I have to daily drive this car for now. I am thinking part of the problem might be with the Down Pipe. I think it is hitting the frame rail at idle, and might pull ove against the frame while accelerating and make the problem even worse.
Though, I am pretty sure(and so is my brother) that we hear knock in the engine.