I had this same problem with my 1.9L w/auto trans, no air condition.

I believe the problem was a faulty auxiliary air regulator valve and
perhaps some vacuum leaks.

I also replaced the idle control stabilizer, crank case breather hose,
and vacuum line connectors, those 3mm short hose segments.

-- Craig

On Wed, 16 Jun 2004 16:37:39 -0700, Mike D. <md03@xochi.com> wrote:
>
> Ok, time to put on your thinking caps.  Can anyone solve this by
> sheer brain power alone?
>
> Details:
>    1985 1.9l Westy w/Auto Trans and Air Conditioning
>    145k miles
>    Compression fair (around 120-125 each cylinder)
>    Recently replaced Digital Idle Stabilizer
>    Recently replaced AFM
>    Timing @ 5BTDC
>
> Symptoms:
>
> When warm runs fine.  Get 17-18mpg on the highway @ 65mph, so I don't
> think there is any gross mechanical problem with the engine or
> mis-tuning.
>
> When cold (60F), it starts right up, but quickly (either immediately,
> or within a minute or two) the idle is rough and the engine will die
> when in Drive, and sometimes even when in Neutral.   I have to keep
> one foot lightly on the accelerator to keep it from stalling.  Within
> about 10 minutes of driving, the problem goes away.
>
> I've tried setting the idle higher when cold (with a few turns of the
> idle adjustment screw).  This solves the stalling problem when cold,
> but then when the van is warm, the idle is way too high (1500+ rpm).
>
> I've gone through the Bently and done most of the electrical digijet
> diagnostics  (resistances of temp senders when cold and hot, etc.)
> without finding anything amiss.
>
> Ideas?
>