Thanks for the response.  I hope that measurement and conditions variations
are the answer but given my luck with the demon van, probably not.

Mike
On 12/5/02 9:46 AM, "Clive" <clive.harman-smith@ntlworld.com> wrote:

> Might I suggest that unless you are doing thousands of miles a week then
> these sort of 'estimates' of fuel consumption are hopelessly inaccurate. I
> have tried to make this point about 6 months ago when I joined the list, but
> to no avail.
> The biggest factors that affect fuel consumption are ambient temperature,
> wind and driving conditions, the engine's vagaries being easily secondary to
> this unless the thing is 'obviouly' running appallingly - in which case, the
> query would be of another nature.
>
> To do a good few hundred miles 'around town' , unless you mean 'around city'
> without intrespersing any other journeys would perhaps be rare, and we all
> know that only on the open road do milesper gallon mean much, as opposed to
> gallons per hour.
>
> I would suggest that the odd drop in consumption is more likely to be a
> fill-to-fill error eventually making its presence felt, unless you are
> actually using a pipette to fill the tank.
> If you plot 'fill-to-fill' and 'running-mean' figures against mileage on an
> Excel or similar chart then you should see these trends balance out....
>
> ..unless you've got a leaky fuel filler pipe (syncro), overfill the tank,
> use different filling stations and pumps or have leaky/drippy injectors and
> let the vehicle idle a lot.
>
> Clive
> '88 Syncro Transporter
> ----- Original Message -----
> From: Mike Miller <mwmiller@CWNET.COM>
> To: <vanagon@GERRY.VANAGON.COM>
> Sent: Thursday, December 05, 2002 4:07 PM
> Subject: Gas mileage
>
>
>> Volks,
>>
>> Every once in a while my gas mileage drops 20+%, from 18 to 15 around town
>> for example.  Then it will go back up.  Nothing done to van.
>>
>> Checked O2 sensor and it's OK every time.
>>
>> Any ideas?
>>
>> If it's bad grounds can I just shoot the damn thing and be done with it?
>>
>> Mike
>>
>