96 3.1 w P0300 code metallic sound but slow

I have a 96 Z26 3.1 with 72K that is running very bad. Sets code p0300 and none other. Lots of blue smoke out the pipe. Has a metallic sounding noise which could be piston slap?? The noise seems too slow to be piston related though. Top speed of the engine is around 4000 rpm but the noise does not go away at higher rpm. If I pull the plug wires one at a time the noise goes away when I pull one of the wires from the coil pack on the back bank. Manifold gasket was replaced 2 months ago. Is it possible I have a bad valve or valve lifter causing the problem. I get no readings at all with my OBDII on bank 2. Any ideas would be appreciated.

1 day later ... I gues no one had any ideas but no matter I did it myself.

What did you do yourself, find the problem? scrap the car? The Beretta forum isn't real busy, so you have to give people time to respond, sheesh!