I had exactly the same symptoms in my Jetta engined Syncro.  I assumed
it was the dreaded Intermittent Syndrome AKA Vanagon Syndrome and 
treated it as such.  I can't say for sure which of the following fixed it as I did 
all three but after a few thousand miles it has not reappeared:
        1. Replaced the fuel filter and added gas cleaner to the tank just in case
        2. Put in a new O2 sensor 
        3. Bought and installed the VW dealer wire harness designed to cure 
        this intermittent problem

r

On Oct 17, 2013, at 1:32 PM, Neil N <musomuso@GMAIL.COM> wrote:

> originally I would have thought Vanagon Syndrome but.....
> 
> dirt in fuel tank blocking outlet or filter/pump?
> 
> What year van?
> 
> I understand VS is caused by "dirty" signals from AFM causing issues with ECU.
> 
> Does your swap use the WBX AFM? I'm guessing, but could a WBX AFM
> cause VS with a Mk2 ECU? Does VS ever happen to the Mk2 Digifant?
> 
> Neil.
> 
> On Wed, Oct 16, 2013 at 10:03 PM, Timmy Evens <monkey_lips@yahoo.com> wrote:
> 
>> ps this is digifant on an inline 4 .
> 
> 
> 
> --
> Neil n
> 
> Blog: tubaneil.blogspot.ca
> 
> '88 Westy http://tinyurl.com/c8rlw6p
> 
> '81 VanaJetta 2.0 "Jaco"  http://tubaneil.googlepages.com/
> 
> Vanagon VAG Gas inline-VR Engine Swap Group:
> 
> http://tinyurl.com/d7gd5ej

Blessed be!

Rowan )O(