Joel: thanks for the info. This Westy BTW is on its third engine (we
bought it for 1200 and swapped in a GEX for another 1500). The first
engine ran out of oil, apparently the owner didn't understand what
the red light meant -goodbye engine!. The second one which we replaced
was just very tired - low compression leaky and busted exhaust pipes
so we replaced it. I believe the body (in very good shape) has about 160,000 miles on it
and judging from the records it is hard to tell if the OXS sensor was
ever replaced (although you would think a new one was put in with the
second engine). The sensor as far as i can tell has only one wire
running from it which connects to the spade inside the compartment.

When the VAN went for its smog test in CA (where we bought everything)
the guy said the OXS sensor was ok (mind you he had to boost rpm to
1200 to pass the idle test). Anyway who can say, sometimes though idle
is erratic and fuel consumption is not as good as it could be 21 mpg (imp-highway).

Any info on the sensors offered by JCW or is this strictly a VW OEM thing?