I had similar symptoms about a year ago, turned out to be a bad throttle position switch.

-Mark

> On Jul 15, 2024, at 10:56 AM, Richard Koerner <rjkinpb@sbcglobal.net> wrote:
> 
>  Oh, Syncro....plastic tank way in the back...but I imagine they too might have some kind of screen on outlet which might get clogged with accumulated debris.  But I know nothing of Syncro fuel system.  Other than it's a real bear to remove that tank!
> 
>    On Monday, July 15, 2024 at 10:48:50 AM PDT, Markus Benne <mbenne@m-bass.com> wrote:  
> 
>   Thanks for that.  Tank was freshly cleaned over the winter.   It was very, very hot out.   And a fresh tank of gas started the day.
> Forgot to mention it's a syncro, but your point is still valid.  
> 
> |   From: rjkinpb@sbcglobal.netSent: July 15, 2024 1:43 p.m.To: vanagon@gerry.vanagon.com; mbenne@m-bass.comSubject: Re: Possible Vanagon Syndrome... |
> 
> 
>  How old is your fuel tank?  Clogged fuel tank outlet will start causing these issues.  Was it a hot day?  High ambient temperatures makes it easy for Fuel Pump to cavitate; these bubbles in liquid fuel cause loss of power and even dying.  Next day after fuel is cold again, the problem disappears.  But then you drive again on hot day, and problem reappears as gasoline in tank warms up to ambient.  Since fuel tank is downwind of radiator, all that hot air flowing by helps also to heat up gasoline.  If clogged outlet from old tank, there is no fix; you've got to replace Fuel Tank. 
> 
>