I have a 2005 Prius for about 14 months and have been very pleased with
it. I had been getting between 59 and 62 mpg up until the Prius had its
first annual service. Now I am getting about 54 mgp. The traffic
conditions are similar and I have not changed my driving style.

Has anyone had a similar experience and/or any ideas on the cause?

John Mulholland wrote:
> I have a 2005 Prius for about 14 months and have been very pleased with
> it. I had been getting between 59 and 62 mpg up until the Prius had its
> first annual service. Now I am getting about 54 mgp. The traffic
> conditions are similar and I have not changed my driving style.
>
> Has anyone had a similar experience and/or any ideas on the cause?

Service done with correct OEM filters? Oil viscosity changed? Maybe you
are actually driving differently and dont realise it?

"Coyoteboy" <coyoteboyuk@hotmail.com> wrote in message
news:1163780419.967935.16160@k70g2000cwa.googlegro ups.com...
>
> John Mulholland wrote:
>> I have a 2005 Prius for about 14 months and have been very pleased with
>> it. I had been getting between 59 and 62 mpg up until the Prius had its
>> first annual service. Now I am getting about 54 mgp. The traffic
>> conditions are similar and I have not changed my driving style.
>>
>> Has anyone had a similar experience and/or any ideas on the cause?
>
> Service done with correct OEM filters? Oil viscosity changed? Maybe you
> are actually driving differently and dont realise it?
>

I don't think incorrect filters or oil viscosity would make a 5 MPG
difference. Besides changes in driving style and road conditions, weather
changes can affect fuel economy, if the heater is used more or the engine
has to run enriched for longer periods of time.
--

Ray O
(correct punctuation to reply)

In article <1163780419.967935.16160@k70g2000cwa.googlegroups. com>
coyoteboyuk@hotmail.com "Coyoteboy" writes:

> John Mulholland wrote:
> > I have a 2005 Prius for about 14 months and have been very pleased with
> > it. I had been getting between 59 and 62 mpg up until the Prius had its
> > first annual service. Now I am getting about 54 mgp. The traffic
> > conditions are similar and I have not changed my driving style.
> >
> > Has anyone had a similar experience and/or any ideas on the cause?
>
> Service done with correct OEM filters? Oil viscosity changed?
> Maybe you are actually driving differently and dont realise it?

Also check for correct tyre pressure.

Re Coyoteboy's suggestion, in past posts I explored factors which
seem to affect my T4 Jul/Aug 2005 Prius' mpgUK. Temperature and
warming of the petrol engine are a biggie: short trips cut mpg in
cold weather; but proper warming can push up the numbers towards
summer's -- on decent roads -- even on a frosty day.

The numbers you quote would not worry me much, though. From your
address, I guess you are talking UK conditions; with temperatures
starting to dip, expect the warming factor to become significant.
(Hmm, did you not see that effect last (2005-6) winter?)

There was some speculation that the grade of petrol might not be
so good in colder weather. UK refiners/suppliers may be shipping
out the grottier go-gunk to filling stations now.
--
Andrew Stephenson

On Fri, 17 Nov 2006 17:58:57 GMT, ames@deltrak.demon.co.uk (Andrew
Stephenson) wrote:

>UK refiners/suppliers may be shipping
>out the grottier go-gunk to filling stations now.

Um... dare I ask what a "grot" is? ;-)

In article <1163786337snz@deltrak.demon.co.uk>,
ames@deltrak.demon.co.uk (Andrew Stephenson) wrote:

> In article <1163780419.967935.16160@k70g2000cwa.googlegroups. com>
> coyoteboyuk@hotmail.com "Coyoteboy" writes:
>
> > John Mulholland wrote:
> > > I have a 2005 Prius for about 14 months and have been very pleased with
> > > it. I had been getting between 59 and 62 mpg up until the Prius had its
> > > first annual service. Now I am getting about 54 mgp. The traffic
> > > conditions are similar and I have not changed my driving style.
> > >
> > > Has anyone had a similar experience and/or any ideas on the cause?
> >
> > Service done with correct OEM filters? Oil viscosity changed?
> > Maybe you are actually driving differently and dont realise it?
>
> Also check for correct tyre pressure.
>
> Re Coyoteboy's suggestion, in past posts I explored factors which
> seem to affect my T4 Jul/Aug 2005 Prius' mpgUK. Temperature and
> warming of the petrol engine are a biggie: short trips cut mpg in
> cold weather; but proper warming can push up the numbers towards
> summer's -- on decent roads -- even on a frosty day.
>
> The numbers you quote would not worry me much, though. From your
> address, I guess you are talking UK conditions; with temperatures
> starting to dip, expect the warming factor to become significant.
> (Hmm, did you not see that effect last (2005-6) winter?)
>
> There was some speculation that the grade of petrol might not be
> so good in colder weather. UK refiners/suppliers may be shipping
> out the grottier go-gunk to filling stations now.

I do remember that my mileage was below 58-60mpg when I first got the
Prius (Sept 2005) and that it was much better later on. That could be
because the weather was getting warmer. I wondered about the service
however because the mpg dropped immediately after it was done - weather
was much the same before and after.

My general impression from the display is that the electric motor is
doing a bit less work than it used to and thought that there might have
been some tweak to the electronics during the service.

I will see how it goes over the winter and spring.