Joel,

I will have to do a good inspection of the vacuum hoses, but most are
in great condition. I replaced the idle control stabilizer about
10,000 miles ago. The aux air regulator has never been replaced. I'll
check that. The coolant temp sensor and connector was replaced about
60,000 miles ago. The van has 260,000 on it. It runs great otherwise.

Thanks for the insight,
Blake Heinlein

On Nov 12, 2007 7:02 PM, joel walker <jwalker17@earthlink.net> wrote:
> > this sounds like a mass air flow meter problem. Anyone have
> > experiences with these types of problems? Any pointers on how to
> > diagnose and/or reasoning.
>
> cheap things first:
> - check all the vacuum hoses on the engine, especially underneath, for
> cracks and rot. sometimes a leak in a cold hose will seal itself as
> the hose/engine heats up.
>
> -next i'd check the idle stabilizer ... that flat thingie/gizmo on the
> left side of the engine compartment.
>
> - then the aux air regulator. it's supposed to regulate the air
> getting to the engine during cold-start/cold-running. looks like a
> smushed trumpet, silverish-gray in color, with two hoses and an
> electrical connection going to it. should be kinda in the front left
> half of the top of the engine.
> this is the one i'd suspect most, after the hoses.
>
> - next, just cause i've had problems with them before, i'd clean the
> connections and/or replace the coolant temp sensor on the thermostat.
> vw used cheap ones and they tend to go bad over time. imho.
>
> the coolant temp sensor and the idle stabilizer are so involved in
> cold start/running that it's very likely to be one or the other,
> though. :(
>
> good luck!
> joel