Thanks guys. I'll definatly try that this weekend. A quick visual
inpsection didn't reviel anything obvious. In having the engine work done,
I had the mechanics install a new O2 sensor, so that would align from a
timeline perspective of when the symptoms started. I'll let you know how it
goes.

On Fri, May 18, 2012 at 8:52 AM, Ken Wilford <kenwilfy@comcast.net> wrote:

> Gregg, as Dennis says, when the van is running poorly, try turning the
> ignition off and then back on again.  If the van runs better for a minute
> then starts messing up again it is definitely an oxygen sensor problem or
> an oxygen sensor circuit problem.  Let us know what you find out.
>
> Ken Wilford
> John 3:16
> www.vanagain.com
>
>
>
> On 5/17/2012 5:05 PM, Gregg Carlen wrote:
>
>> Hi all,
>>
>> My 1990 Westy (automatic, 2WD) has been running great since I had the
>> heads
>> redone, tune up, coolant replaced, exhaust repaired, etc, this spring.
>> Last
>> summer, I had the AC repaired (new hoses, dryer, compressor and condensor)
>> and things worked great last Fall.
>>
>> Now that the weather is getting warmer here in Northern Virignia, I'm
>> finding my need (desire) to use the AC more often. So, I started using it
>> about 2 weeks ago and whenever it runs for about 30 seconds, then the
>> engine seems to 'bog down' and power is lost. To explain that a little
>> better, when I'm driving and this occurs, I can maintain speed for a
>> couple
>> minutes, then I loose power (almost as if fuel was being starved) and the
>> van starts to slow down. If I push on the accelorator more, the engine
>> continues to decrease power but is trying harder and the faintest black
>> smoke starts to come out of the exhaust. As soon as I turn the AC off,
>> everything resumes to normal in about 2 seconds (power, speed can be
>> increased, no black smoke). Another symptom is if I am stopped a traffic
>> light (or for any other reason) with the AC on, the engine will stutter
>> and
>> reduce the idle RPMs until it stalls out.
>>
>> There have been a few occasions where this 'AC reduces power' symptom
>> didn't occur and everything worked fine. It seems like only the last 2
>> weeks has this started to act up (again, keep in mind I only started using
>> the AC this spring in the past 2 weeks).
>>
>> A few other factors that 'may' be related and influence what is occuring.
>> FYI, I've had the van for about a year, so only last fall did I use the AC
>> (and didn't experience any issues). The AC will ONLY turn on (AC
>> compressor
>> clutch kicks in, fan blows cold air) when the two AC switches (fan speed
>> and thermostat switch) are turned up to their highest settings. If either
>> is turned to a lower setting, the AC does not operate.  Also, the PO had
>> removed the stock radiator fan and replaced it with an aftermarket that is
>> controlled by a manual toggle switch (attached to the steering column).
>> This 'AC reduces power' symptom seems to occur regardless if the radiator
>> fan is turned on or off. I also have a flashing coolant light, but this
>> van
>> has always had that problem (I need to search the archives to refresh my
>> memory about the cuases for that and fix that, too).
>>
>> I saw an archived thread about an AC idle stabilizer, but that was for a
>> 1.9l. Does that exist on the 2.1? Given the symptoms above, could that
>> component be causing this if its failing?
>>
>> Any suggestions of where to start troubleshooting/testing?
>>
>> Gregg
>> 90 Westy (Blueberry)
>>
>>