Last year I had similar issues. It turned out to be a bad fuel pressure regulator. 
  Jeff Woodall      woody"keep on pushin'"

    

> Date: Mon, 3 Nov 2014 09:26:11 -0500
> From: sartin@GMAIL.COM
> Subject: Re: Still trying to diagnose an off idle stumble.
> To: vanagon@GERRY.VANAGON.COM
> 
> I did adjust the switches to Bentley standards. I also tested the switch
> and it seems to work as required.
> 
> I will be trying a new afm thanks to a list member (thanks!) but MAN this
> is a frustrating problem!
> 
> Thanks again all.
> 
> Blake
> 
> On Nov 3, 2014 1:40 AM, "Karl Wolz" <wolzphoto@q.com> wrote:
> >
> > I'd take a look at the throttle position switch adjustment. This is
> critical for driveability.
> >
> > Karl Wolz
> > Sent from my electronic umbilicus
> >
> > > On Nov 2, 2014, at 6:24 PM, Blake Sartin <sartin@GMAIL.COM> wrote:
> 
> > > Vanagon off idle stumble: http://youtu.be/Eeo_vfue-q0