the 300 code could just because it needs a tune up bad. one is the plug closest to the coil packs, 2 is the one by the alt.
that vac manifold the one jipple with tape should be capped off in a 04 car. you can buy vac line caps.
does it smoke all the time? or just the one time? or at every cold start? valve seals come to mind if its oil you smell out the pipes.
04 iirc might have the new metal intake gaskets factory, so chances are lim gaskets are ok. the blower might have metal gasket, if it does you can reuse it. its 40 bucks new...