The 2000 rpm idle when cold is apparently typical of 2003-2006 model Matrixes and Corollas - the Matrix forums grumble about it endlessly, but also note that if it stops happening, there's a significant engine management problem.  It's all about getting the catalyst to 'light up'.

James
Ottawa, ON

> Date: Mon, 28 Jul 2014 16:59:37 -0400
> From: d23haynes57@HOTMAIL.COM
> Subject: Re: O2 sensors brand quality difference?
> To: vanagon@GERRY.VANAGON.COM
> 
> Back in the days of carburetors and chokes that was done just keep an engine
> from stalling. After the original Audi unintended acceleration fiasco I
> can't imagine any late model car being designed that way. Especially with an
> automatic.
> 
> Dennis
> 
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> James
> Sent: Sunday, July 27, 2014 11:18 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: O2 sensors brand quality difference?
> 
> Our '03 Toyota Matrix idles at 2000+ rpm in colder weather to get it's
> catalytic converter to 'light up' - and the cat is located immediately after
> the exhaust manifold!
> 
> In other news, I've learned the importance of avoiding exhaust leaks - what
> I thought was a faulty idle stabilisation valve turned out to two small
> exhaust leaks - one in an exhaust gasket and the other where the cap on the
> CO sniffer port had fallen off.  Thanks to Frank Condelli for diagnosing
> that!  Our '91 now goes into closed loop much faster, AND idles much more
> reliably when cold.
> 
> James
> Ottawa, ON
> 
> > Date: Fri, 25 Jul 2014 17:00:02 -0400
> > From: d23haynes57@HOTMAIL.COM
> > Subject: Re: O2 sensors brand quality difference?
> > To: vanagon@GERRY.VANAGON.COM
> >
> > The Vanagon operates the O2 sensor heater continuously. Since it is so far
> away from the engine it is needed especially for idle and low speed
> operation. It is used on many vehicles to get them into closed loop
> operation as soon as possible. Many vehicles even have heated catalytic
> converters and sometimes other tricks are used to get the cats "lighted". On
> my 1992 600 SEL the transmission upshifts are delayed when cold to get the
> revs up to help get the cats lighted.
> >
> > Dennis
> >