one other thing ...
I always feel better with a fuel pressure gauge on the fuel system ..
while I'm sorting through weirdness, or at least for a while if other common
things are not being found out of whack.
----- Original Message -----
From: "John Rodgers" <inua@CHARTER.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Saturday, October 09, 2010 3:56 PM
Subject: It continues - Engine RPM Hunting 200-500 rpm

>  I have been tinkering with my 91 Carat and have still not resolved the
> hunting issue.
>
> On cold start-up I have to play with the pedal to keep it running - up
> and down between 1000 and 2000 rpm. As it warms up, it begins to settle
> down. Not as much footwork to keep it running. Eventually it will idle
> smoothly around 1000 rpm. But if I try and accelerate the engine above
> the 1000 rpm range - it goes into the hunt mode again. Around 2000 rpm
> it will run relatively smoothly.
>
> The injectors have been serviced and run in another of my vans, so I
> know they are good. All the hoses are good, and I carefully inspected
> the vacuum lines just to be sure. The crankcase vent host is new.
>
> I disconnected the idle stabilizer valve after warm up, and restarted.
> It was a little rough to start, but after start-up it smoothed out at
> 1000 rpm like before, and still would not run properly between 1000 and
> 2000 rpm.
>
> I have not disconnected the O2 Sensor yet.  O2 sensors have caused rough
> running on my other vans, and smoothed out when disconnected, but this
> is a little different.
>
> So apparently, this takes me to the throttle switch - I think. But this
> engine has only 114,000 miles and is clean, so I'm suspicious about
> whether it's the switch or not. Never tampered with the switch before,
> so a little unsettled about working on that.
>
> Any  input on this would be appreciated.
>
> Thanks,
>
> John
>
> --
> John Rodgers
> Clayartist and Moldmaker
> 88'GL VW Bus Driver
> Chelsea, AL
> Http://www.moldhaus.com