Thanks for the feed-back so far, I'll begin to check into things a bit more
with the vacuum hose.  I have been suspecting the temp 2 sensor as well but
the throttle body is relatively new so I am putting that in the
possible but unlikely category.

The last two days - it has started normally - with the idle bumping up for
about a second or to 2000 and then coming down to about 1100 before
settling once warm to about 950.  So whatever the situation - it is
intermittent.

Bruce

On Sun, Sep 27, 2020 at 10:53 AM Stacy Schneider <vwcrewman@gmail.com>
wrote:

> I’ve just gotten though fighting this fight. Have you checked the Vacuum
> hose that goes from the intake plenum to the power brake booster line?
>               I had idle issues that would run fine after about 2 minutes.
> I pulled on the hose and my idle increased. Once removed there were 4 holes
> in hose. The wire inner support had rusted and was abrasive agAinst the
> hose and caused a leak.
>            While in place you didn’t notice it because of the arc of the
> hose. Once removed the problem was obvious.
>              If I could post pics of the hose here, I would.
>               The correct hose is hard to find and not cheap. I write it
> off as I fixed it myself and it’s way cheaper then what my Mech would have
> charge me and I know I have the correct hose.
>                My boxer now starts up and idles  perfectly right from the
> first start.
>
>                             Stacy
>
> On Sun, Sep 27, 2020 at 10:13 AM Dan N <dn92610@gmail.com> wrote:
>
> >  hi Bruce,
> >
> >
> >
> > I had a similar idle problem with my van as yours. A rebuilt ICU didn't
> >
> > solve the problem... The problem was solved after I replaced the rubber
> >
> > seal behind the throttle body and replaced the Temp2 sensor... I don't
> know
> >
> > which one solved the problem, but I know a small leak the throttle body
> >
> > seal can cause erratic idle and "lazy" slow to react Temp2 sensor can
> >
> > cause erratic idle too.
> >
> >
> >
> > I hope this helps.
> >
> >
> >
> > On Sat, Sep 26, 2020 at 4:34 PM Bruce Todd <beeceetee@gmail.com> wrote:
> >
> >
> >
> > > Good day everyone -
> >
> > >
> >
> > > I am curious to know whether other stock vanagons typically - when
> > started,
> >
> > > spike very briefly to about 2000 rpm for several milliseconds and then
> > drop
> >
> > > to about 950?  Eventually as the vehicle warms the idle drops a little
> > bit
> >
> > > more to about 900 rpm for regular operation.
> >
> > >
> >
> > > That has always been the way my van (2.1 digifant) has started when
> >
> > > healthy.  I replaced the control unit about 2 years ago after having a
> >
> > > fluctuating idle that would slowly begin to increase to 1800 to 2500 to
> >
> > > 3000 rpm as the van warmed up and when the van was in neutral or
> stopped
> >
> > > with the clutch in.
> >
> > >
> >
> > > During this issue - I swapped out the ICU with one I borrowed from a
> >
> > > mechanic I have known for many years and everything went back to normal
> > and
> >
> > > so I ordered a new ICU and haven't looked back.  Again the start up
> > process
> >
> > > whether with the borrowed or the new ICU had the very quick spike in
> rpm
> >
> > > once started - enough to kick the battery / alternator indicator off
> and
> >
> > > then would settle down to about 900 rpm or so.
> >
> > >
> >
> > > Last week - I started the van and the idle was flat - no quick spike
> and
> >
> > > just set high enough not to stall - about 850 rpm or so.  I had to
> nurse
> >
> > > the motor a little with the throttle for about a minute and then give
> it
> > a
> >
> > > little gas to shut off the battery indicator.
> >
> > >
> >
> > > Once I get through the rough idle on start up - it drives fine.  The
> idle
> >
> > > stabilizer vibrates with key on and prior to start up and the throttle
> > body
> >
> > > "clicks" in the low throttle and higher throttle position.  I plan to
> go
> >
> > > back and try out another ICU - but before doing this I wanted to know
> if
> >
> > > this sounds like a problem with the ICU or whether it could be another
> >
> > > gremlin lurking in the engine compartment.
> >
> > >
> >
> > > Other than this little issue - we have a great summer of camping and
> >
> > > problem free driving.
> >
> > >
> >
> > > Bruce
> >
> > >
> >
> > > 86 Syncro Westy
> >
> > >
> >
> > --
>    1989 Swedish Tristar with Aluminum gates and Atiwe 16" Wheels.
>     Oldest son is an Eagle scout.
>