Wet plugs on a '85 5000s

[David Templeton]

Hi all

I am still in the process of getting the wagon ready for emissions.  When
the engine gets warm the idle starts going up and down from about 800 to
1200rpm. I also pulled the plugs and they were gas-wet black. I am figuring
it is running rich, it has been suggested the O2 sensor may be toast.  Any
insights would helpful, again this is non-turbo beasty.
Thanks
David Templeton
'85 5000s wagon - almost there :-)