> There recently was a thread regarding poor running of a Vanagon after a tune up.  I read the conclusions and don't think it covers my problem although It is related...
> I just installed a new O2 sensor.  It was a Bosch which needed to be spliced in.  I know how to solder and made some fine connections which were covered with shrink wrap afterwards.  Anyway,  it's now running really crappy...Smoke, black tail pipe, sounds like it's missing....the works.  It did run fine before the switch AND I unplugged the O2 sensor and went for a test and it ....dare I say, ran great.   Whats Up?

Well, if it runs well when you disconnect the O2 sensor, then you have found
your problem.  If it runs rich with the O2 sensor connected, then the van
thinks it is running lean and is giving it more gas -- it is wrong.  The
"lean running" is a low voltage -- like a zero volt reading, which would imply
that you got the wire connected to ground.  Unplug the O2 sensor and run the
engine. Take a volt meter and see what the sensor is putting out -- I'll bet
it is zero.

Malcolm