I purchased my '87 syncro westfalia in March of 2000 from our local
Anchorage Alaska VW dealer.  It stranded me on the side of the road a week
later.  A quick trip to the VW dealer and the oxygen sensor was replaced.
Problem solved.

About six months later, the van was idling roughly, and I noticed black
smoke at the tail pipe.  I replaced the oxygen sensor with a Bosch unit with
the correct VW plug already attached.  Problem solved.

Yesterday I noticed the van was idling roughly, and I noticed black smoke at
the tail pipe.  I am tired of thinking I am solving the problem by replacing
the oxygen sensor.  Any ideas?

John Cooper
87 Syncro Westy
"Arctic Westy"