George,

BTDT.

Before you start doing all kinds of other checking, first be sure your
idle speed is correct with the engine warm and the ISV disconnected. If
it is not, it will introduce all kinds of anomalies.

Warm the engine, shut it off, disconnect the ISV, then restart and check
the idle rpm. Adjust as necessary. Shut down, connect the ISV, allow the
engine to get cold, then restart - this is to check the ISV for cold
start control. Note the rpm, then note it again when the engine is warm.

When cold the ISV circuit should kick the idle up to keep it from
stalling, when warm, the idle should drop back to 850-900 RPM.

Good hunting.

John Rodgers
88 GL Driver

George Goff wrote:
> I thought I had seen about every kind of weirdness which a Vanagon can
> exhibit, but I am open to any and all suggestions regarding this most recent
> bout of perverse running.  At times, my '90 Syncro idles at about 2K.  The
> strange thing is that when it is idling high, if I hold it with the brake and
> release the clutch slightly, I can drag the engine speed down to 1K and it
> will hold that speed rock solid until the throttle is blipped.  As the engine
> has been gone over quite a bit, this one has me stumped.  Hopefully someone
> will have had the same symptoms and he can save me untold hours of chasing my
> own tail.
>
> Thanks, one and all.
>
> George
>