I love a story with a happy ending! And I agree that it's a great idea to crawl around under our Vanagons from time to time, it is both preventative and therapeutic. 

Regards, Peter
KraikerPhoto.com
Skype: pkraiker

> On Jun 30, 2014, at 11:21 PM, Don Hanson <dhanson928@GMAIL.COM> wrote:
> 
>  Recently I posted asking for help with what I thought might be Vanagon
> Syndrome...bucking and missing after sustained driving, but also at random
> moments..This was on my 84 tin top with an inline VW ABA/hybrid Jetta-based
> motor and a 5sp manual transmission.  Digifant engine management using
> mostly the vanagon parts.
> 
>   The general consensus was that I should check the "usual suspects"...O2
> sensor, Temp II sensor, grounds, etc etc. and then go after the air flow
> flapper thingy that causes Vanagon syndrome..or so it is said.
> 
> This has been a hard used and relatively trouble free van for me.  Worker
> Van....  I don't particularly relish chasing down an unexplained and
> significant problem with the electronic fuel injection, but I needed the
> van running well because it's now also my main toy hauler fun vehicle.
> 
>     So I went to the O2 sensor first and found the signal wire was down to
> about one strand intact.....just about broken completely..   I installed a
> new O2 sensor.
> 
>  While I was under I noticed there was an unconnected vacuum line at the
> bottom of the throttle body....On the inline that is right above the
> exhaust, where the O2 sensor lives, right in front of my nose
> there.......the loose vacuum line controls an intake air warm up circuit,
> and.... that open vacuum port at the throttle body, that was probably what
> has been causing me a slight hesitation, ever since last fall, when I
> resume throttle.  Plugged that back in.
> 
>  Tested the Temp II sender as the Bently says and that was good, but I put
> another in anyhow and cleaned all the connectors...
> 
>  Voila!  It again runs perfectly        And the bonus is my fuel economy
> went back to where it should be....I think.   I have only done one tank of
> driving since the fixing....150 miles in 50mph winds...out and back...and
> 150 miles of mixed driving but I again got almost 24mpg where I have been
> getting down to 21 and my last tank, with the problem ongoing, that was
> only 20mpg..   The resume throttle hesitation is gone, too.
> 
>   So, I was thinking..."Oh, the old van, it's just getting tired..that is
> why the fuel economy has dropped a little and why it sometimes lags when
> you get back in the gas"....But thanks to the Serious bucking and missing
> episodes *forcing me* to actually crawl under and work on stuff, I found
> simple fixes that restored the van to nearly perfect running again...all
> without spending a dime...had the spares under my bench seat..
> 
>  That is the bright side, and I am going to relish that thought...
> 
>   Don Hanson