Greeting vanagonauts. I recently (approx 500 miles ago) replaced my O2 
sensor after having a problem with my 1990 Wesfalia that caused it to 
bog down and quit running after warming up. I am assuming that this 
happened when the coolant temp sensor told the ECU to turn the heater 
off on the sensor. When I unplugged the sensor the problem went away. 
Since my sensor had more than 60K on it which is the VW replacement 
interval, I replaced the sensor. After Installing the sensor everything 
seemed to be back to normal. One other bit of info that is worth 
mentioning is that I have an O2 sensor monitor that indicated that 
everything went completely rich when the problem occurred. It showed 
this type reading with the original sensor issue and the new sensor 
issue. My thoughts are that the problem might be with the small guage 
coax type cable that sends the sensor signal to the ECU grounding out 
 from the inner sensor wire to the outer metal sheathing that I believe 
is grounded to the chassis. I had a similar problem with this cable 
once before and I believe that I cut a small piece off of the end and 
put the connector back on. Knowing that most types of coax cable will 
eventually fail, I am wondering if anyone has had a problem similar to 
this with this cable and if so where did you find a replacement. I 
believe  that it is wrapped with the other wires in the main harness 
section that goes to the ECU so I would probably just run another piece 
that would be wire-tied to it rather than risk disturbing the rest of 
the original harness and causing a problem with another wire. Maybe 
there is another problem. I think that if it were a problem with the 
not so old coolant temp sensor I would have some type of symptom with 
the O2 sensor unplugged. I thought that I would pick the collective 
craniums of the group since,  as is usually the case someone has BTDT 
with this issue. I'm just not the type to want to continue riding 
around with the o2 sensor unplugged with the price of gas and the extra 
emissions that I would produce that are not good for the environment or 
my catalytic converter. Thanks for any input that you have. I am 
suddenly having to drive my older van a lot due to a temporary 
employment situation and it's begging for attention.

David Clarkson
90 Westfalia about 200 mi  short of 300K-now what will I get it or do 
for it for this milestone birthday? It has been asking for cosmetic 
surgery for some time now (rust repair and paint)!