Hi Dave,

        Sadly that is well known as a unlikely cure.  The sensor tested out fine.  But due to a needed muffler a new one went in.  It also tests out perfectly.

Interestingly, Dennis predicted this would be the case and that it would be something else in the system. 

It will be so interesting and satisfying to solve this mystery.

Keep the tips coming.

Eric Caron 
84 2.3 GW with 1.9 fuel management 

> On Jul 27, 2022, at 11:57 AM, David McNeely <davmcneely40@GMAIL.COM> wrote:
> 
> So if the problem only manifests itself with the O2 sensor plugged in, put
> in a new O2 sensor.
> 
> On Wed, Jul 27, 2022 at 6:23 AM Eric Caron <ericcaron96@comcast.net> wrote:
> 
>> Hi collective mechanical mind.
>> 
>> Reporting back still not solved running issue on 2.3 with 1.9 fuel
>> management.
>> 
>> Many steps still not done as friends are busy and summer is full of
>> activities.
>> 
>> Issue is still.
>> 
>> Van idles high.
>> Screw for idle control closed to max.
>> Checked for vacuum leaks and not finding them.
>> Tried to check timing but idle too high about 1,000 rpm and now and then a
>> surge to 1,200 RPM .
>> 
>> Engine  stumbles only when O2 plugged in and engine warm.  From a stop
>> press excellerator and 2 out of three times it will hesitate stumble or
>> skip.  Then find itself and go.  No O2 and it seems fine.
>> 
>> Still need to try a friends ECU
>> 
>> I’m hoping to soon have most of a recently working 1.9 ignition system to
>> have for testing and spares.  I know diagnostics is better but still having
>> working spares will make maintaining the old system easier.
>> 
>> I don’t need it to be perfect but this skip and running rich needs to be
>> resolved.
>> 
>> Other then this van is currently ready for a long distance trip.
>> I recently discovered that a long term friend from bus events has a twin
>> to my van, year, color, and even the engine and fuel management.  Currently
>> enjoying a trip up and down the east coast.  This gives me hope for a good
>> running van in the future.
>> 
>> Any additional tips are always appreciated.
>> 
>> Eric Caron
>> 
>> 84 GW 2.3 with 1.9 fuel management
>>