Code P0301 and P0320

Been lurking for a long time awesome site! Here's my first post. On my 1998 XJ 4.0 5 spd with 225k miles I've been getting an ever increasing tick when accelerating, and a low end rattle and piston slap from the engine at idle. Exhaust manifold is new and there is no exhaust leak (I've checked with a stethoscope). The tick is a top end metallic sound, deeper than an exhaust leak. It runs perfect, great power, and gets 22mpg average. Today the CEL came on and I got codes P0301 #1 misfire and P0320 which it says is CPS related. The CPS is obviously a known problem, so could the CPS cause the #1 misfire or what else could it be? Any tips?