Sounds like O2 sensor.

On 8/4/08 9:18 AM, "Bruce Todd" <beeceetee@GMAIL.COM> wrote:

> And now more riveting vanagon news related to my fuel line and air
> distributer replacement saga.
>
> After correctly putting the appropriate plug wire on the appropriate spark
> plug my van fired up instantly and idled nicely...talk about a ninnyhammer!
> I was quite impressed on how quickly it fired up (possibly a new battery I
> installed during this whole mechanical affair). Everything was going great
> until about 2 minutes into my test drive when the idle dropped from a
> steady 1000 rpm and began to moderately kick up and down from around 850 rpm
> to 1000 rpm.
>
> I could detect a pungent emisson smell and the sound from the exhaust became
> slightly louder and raspier.  I could still drive the van but had lost quite
> a bit of power - very sluggish - however it didn't stall out and got me back
> home.
>
> Possibly an adjustment is required to do with engine temperature - once the
> van warms up?  Idle adjustment screw?
>
> I'm just covering my tracks with the Bentley now - any input is welcome.
>
> Thanks.
>
> BT