Your NJ mileage problem is surely a result of wintertime oxygenated fuel.
Don't know the chemistry involved, but from October to April fuel mfgs. in
congested areas of the country put in a decongestant, I mean additive that
brings it's own oxygen to the combustion process.  The O2 sensor sees this
oxygen and supplies more fuel.  Somehow this is supposed reduce emissions in
the winter.

Gary
----- Original Message -----
From: Beth & Jere Hawn <jbrschawn@EARTHLINK.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Sunday, December 10, 2000 2:31 AM
Subject: Re: I am almost ready to shoot my vaagon!

> Hello,
>
> Not to rag on NJ, however if you are having this problem in NJ, I have and
> experience where my mileage dropped drastically until I left the area in
NJ
> that I was visiting.  It was a miraculous cure.  I almost thought for a
> moment that I was loosing mileage at the pump.
>
> Jere
> 90 GL
> 88 GL
>
>
>
> ----- Original Message -----
> From: "gcarcher" <gcarcher@HOME.COM>
> To: <vanagon@GERRY.VANAGON.COM>
> Sent: Saturday, December 09, 2000 5:31 PM
> Subject: I am almost ready to shoot my vaagon!
>
>
> > Dear vanagon List Members:
> >
> > My 83.5 Wasserboxer runs better than ever during the 60,000 miles I have
> > owned her.
> >
> > Yet, the MPG has been declining over the last two months - down from 18
> mpg
> > to 11.5 mpg. No fuel leaks. new Plugs, rotor and distributor cap. Recent
> > fuel,  air filter and pump.
> >
> > New Oxy sensor.
> >
> > My catalytic converter is empty of any catalyst and the muffler has been
> > cleaned out of all catalytic debris. There is a bit more power and
cooler
> > running engine with a "throaty" exhaust note.
> >
> > Ignition tuned 3 times in the last 3 months.
> >
> > Exhaust stinks with partially burned fuel at idle.
> >
> > Got any Ideas before I pull the trigger0?
> >
> > Captain Meno.
> >
>