HELP!! I failed emissions!!

[Carl & Dawn]

Hey there people,

I'm in CT and the three emissions that are tested apparently are
Hyrdocarbon, CO, and NOx.  I JUST BARELY failed on the carbon monoxide
set - everything else was well below the EPA parameters.  The pamphlet
that they give you "...So, your car has failed emisssions, what do you
do now?"  says that the problem is "most likely" a bad sensor or
something with the EGR system.

Can someone shed some light on what would be a good plan of attack.  It
is an '84 4KQ and I obviously do not want to spend a mint to get it to
pass and I would prefer to do the work myself.

Thanks in advance.
Carl