Correct,
When trying to do the baseline mixture adjustment, "The O2 sensor must
be disconnected" with the ignition turned off. If you disconnect it with
the ignition on, the adjustment will be off set by the last sensor based
adjustment. This partly due to the leakage input voltage to the ECU
being sufficient so the ECU thinks that is now normal so no more
adjustment is made. The sensor actually loads down and absorbs this
leakage voltage when it is not producing voltage. (hope this makes sense
to you). Turning the ignition off and back on with the sensor
disconnected will bring it back to the default base line.

Dennis

-----Original Message-----
From: THX0001@aol.com [mailto:THX0001@aol.com]
Sent: Tuesday, September 20, 2005 8:27 PM
To: vanagon@GERRY.VANAGON.COM; dhaynes@optonline.net
Subject: Re: quick question - running rough after 2 minutes

In a message dated 9/20/05 6:42:16 PM, dhaynes@optonline.net writes:

<< The computer does not retain anything after the ignition is cycled.
No
memory there at all. >>

I cannot believe this is true; I have to defer to the service literature

published by VW which says, in more than one place:

"With the ignition switched off, disconnect oxygen sensor.  The oxygen
sensor
must be disconnected with the ignition off in order to cancel a MEMORY
function in the E.C.U."

George