I have an 86, with 12k on a rebuilt Boston Bob engine, I just did my 1st
major service, plugs, wires, 20w50 synthetic, mann filter, new belts, new
fuel filter, air filter, cap and rotor, and then timed it with a light gun.
Just before the service I was getting about 125-150 miles out of a tank, and
it is no better after.

I am guessing that I am running rich.  Upon review of the archives, all
signs point to the o2 sensor as the culprit.  I took it out, it is a little
grey, there is some soot around the base.

Is there a way to test it on the vehicle?  Is there way to adjust the
fuel/air mix?  How do I know I have it right?  What are the consequences of
taking it out, plugging the hole and tie wrapping the sensor to the frame?

Regards,

John N. Motlagh

1986 East Texas Westy