Roger,

I had a similar problem with my '85.  I'm betting it is an O2 Sensor
problem rather than an ECU problem.  Before replacing the Sensor though
check the continuity on the ground wire (one of the white ones).
The '85 has the shielded green wire and the shielding is grounded in
the ECU connector.  On mine the ground splice had corroded so it was
not functioning causing the O2 readings to be misinterpreted by the ECU
which caused power loss and stumbling when I hit the gas.  I replaced
two O2 sensors before getting smart enough to check the wiring.  An '86
should have the three wire O2 Sensor so my guess is the ground wire is
not grounding.

Chuck
'85 Wolfsburg Westy - 'Roland the Road Buffalo'

>Just added an 86 GL automatic to the fold. The PO's mechanic (also a
>PO) says it needs a new ECU.
>The black wire to the O2 sensor was unplugged to fix the problem. I
>plugged it back in to see what the deal was. It loses power and
>stumbles when you give it gas.
>Unplug the wire and it's fine. Is this really an ECU problem or should
>I try a new O2 sensor? His mechanic wanted to charge him $800 for a
>used unit!
>The motor is a rebuild with 30,000 on it. Runs smooth, love it. Can't
>say how old the O2 sensor is.
>Thanks
>
>Roger VanTill
>89 Westy
>86 GL