Sounds like a great trip Bruno. My experience is a slow coolant leak becomes a big leak very quickly. Catastrophically :). I drove mine with a small leak but stayed close to home for the inevitable kaboom. 

Jeff 
Now with a Boston Bob 2.1

Sent from my iPhone

> On Oct 1, 2017, at 4:42 PM, Bruno Walser <bruno.walser@COMCAST.NET> wrote:
> 
> My wife and I just came back form a 2000 mile trip to NovaScotia, Prince
> Edward Islands and to the Madeleine Islands. On our way up, in Maine
> intermittently the car would start to jerk/hesitate. This happened not only
> at high speeds. It was not the "Vanagon syndrome". I disconnected the
> oxygen sensor and things got better. So I got a new oxygen sensor installed
> in Nova Scotia. Car seems to be running ok again, although it felt just a
> it off.
> Then on our way home the hickups came back and it started to get worse. On
> the border crossing back into the US, I barely made it through customs. The
> car would still idle normally, but would choke as soon as I opened the
> throttle.  By reving the engine and use of the clutch I was able to get the
> car up to speed so we could keep going. We made it back to New Hampshire
> but barely made up to hill to our house.
> Yesterday I tried to figure out the problem. Now the engine wouldn't even
> start. I took the spark plugs out. They were completely fouled. I installed
> new ones. The engine starts up and idles normally, but again it seems to
> hesitate and jerk and lower RPM's and low load. I disconnected the oxygen
> sensor again and things seem to be a bit better. I checked timing,
> temperature sensor, throttle switch, compression, all seems to be ok.
> 
> I assume the spare plugs fouled up because the engine was running too rich.
> But why? Could it be that the oxygen sensor got damaged again on our way
> home? If so, why?
> 
> BTW, I failed to mention that the engine developed a head gasket leak, but
> it seem still small (barley lost any coolant on our trip). I was told that
> the leak should not cause any running issues, at least as long as it
> doesn't become a more serious leak.
> 
> Any help or tips what I should check are greatly appreciated.
> 
> Bruno
> 86 Vanagon Westy, 2.1 WBXwith Digifant