Back on Nov 29th, Joe Beckham on the list asked about them as well.  I
thought I had CC'd the list with my answer (apparently not).  Here it is in
it's entire form:

Since no reference materials list a 4 wire for the 2.1, you will be left
with using a Universal 4 Wire Sensor.  Your best bets are the following
Bosch units (prices are approximate):

15734 $86
15736 $104
15738 $104

All the above have 25 1/2" Leads, but probably have different splice
connector pieces which may account for price differences.

Hope this helps
--
Jim Thompson
84 Westfalia 2.1 "Ole Putt"
73 K Ghia Coupe "Denise"
72 411 Station Wagon "Pug"
oldvolkshome@gmail.com
http://www.oldvolkshome.com
*Have a Happy & SAFE Holiday*
**********************************
On 12/20/06, Kenneth Lewis <kdlewis@northstate.net> wrote:
>
> I would like to try a four wire O2 sensor. Anybody have a part # for a
> generic unit that has worked for them?
> TIA
> Ken Lewis
> http://neksiwel.20m.com/
>