My 86 is running rich so that after a dozen miles or so the spark plugs
are black and sooty resulting in a rough running engine and some black
smoke at the exhaust.  Compression is good  and timing and idle are at
specs.  I've changed the idle stabilizer valve (it needed it).  The
temperature sensor2 at the thermostat housing gives what appears tobe
reasonable readings at different temperatures although it is difficult
to get the probes at the site easily.
What are some of the other things I can look at given the above
circumstances?  How does one check out and oxygen sensor? etc.,etc.,
etc.......
Thanking you in advance,
Alex
P.S.  My thanks to those that responded to my last message regarding
timing marks and tach setup.  You were absolutely correct on all counts.
Again, thanks.
Alex