hydrocarbons

[Clint Harames <charames@cabletron.com>]

Adam,
    I just read the letter you posted about high hydrocarbons.  I can
tell you what to look for if you provide the rest of the reading
produced by you emissions test.  Having only the HC reading to go on
gives only part of the story.  You HC could be high because of low CO.
Low CO indicates a lean burn which usually results in a lean misfire.
The incomplete combustion (from lean misfire) puts raw gas into the cat
(HC).  Assuming you don't have any vacuum leaks causing leanness, the
next most likely cause is a bad oxygen sensor.  When they wear out they
send false signals to the computer.  The O2 sensor may be telling the
computer your motor is running rich when, in reality it is not.  The
computer tries to compensate by leaning the mixture.  Anyway, more
details are needed....