Could be the O2 sensor. Could be the idle stabilizer system. My van
stumbles when the idle stbilizer vlave wire is hooked up. Disconect it
and it smooths out.

You can test the O2 sensor with a meter.

Regards,

John Rodgers
88 GL /Driver

Roger Van Till wrote:

> 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
>
>