Well truthfully, you don't really want us to just start shooting from the hip on this do you? That is the quickest way I know to relieve your wallet of it'* green matter. The thing about diagnostics in most instances, is that they start with the simplest, least expensive possibilities and go from there.
IMO, as already said, diagnosing an engine you're not familiar with (meaning - it'* condition) starts with the tune up. This gets you looking at things like the condition of the plugs, wires, coils, vacuum lines, etc. While these items will not likely fix your knock problem, their conditions can give you valuable hints as to what may be wrong.
Keep your computer nearby and let us know what you find. We'll be here to offer what advice we can.
Mike: 1997 SE w/ 183K, aka White Horse
, Gutted Airbox w/K&N, drilled 180* t-stat, tint all around, clear corners w/SilverStars, "PONTIAC" light up tail, PEMs, NGK TR55s