According to a 2002 Impreza ServiceManual that I have ~

Idle speed at Park/Neutral position (A/C OFF)                   650(MT)         700(AT)

650 is where mine idles most of the time with brief dips to 637 &  
bumps to 662 ~ on very rare occasions

it will do a brief dip 625 ~ Idle is very smooth @ any of those RPMs.

        If you want it to run @ 700 you can alter the ECU to think it is in  
an A/T ~ My ECU was originally set

for A/T & I switched it to M/T ~ It's a real GasSipper @ 650RPM, only . 
17GPH on SummerGas.

                                                        ORR ~ DeanB

On 7 Aug , 2013, at 9:13 PM, Dennis Haynes wrote:

> Being this is a Subaru engine isn�t the idle electronically  
> controlled? 650 rpm seems low and that could be part of the problem.  
> The CO of .15% may indicate a "lean miss fire" condition. The HC  
> reading 0f 87 at 2,500 rpm is also a problem. I'll bet a new  
> catalytic converter will take care of both problems. I would do a  
> compression and leak down test to make sure all is in order, then  
> look for vacuum leaks or bad injectors. The should be able to check  
> emissions pre and post the Cat to see if it is working.
>
> Dennis
>
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On  
> Behalf Of Gmail
> Sent: Wednesday, August 7, 2013 12:17 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Failed Emissions - High HC at Idle
>
> Just failed UT emissions with high HC at idle. Strange thing is this  
> is the exact set up I had before installing a different zero time  
> rebuild due to the first using too much oil. The only difference  
> with this new rebuild is the idle is now around 650 rpm where as the  
> original rebuild idled at 800-900 rpm.
>
> I�m wondering if I adjusted the idle back up to the higher numbers  
> it might pass.
>
> Idle       CO2 12.96 �  O2 3.14 �  HC 287 � CO .15
> 2500     CO2 14.75 �  O2 .47 �    HC 87 �   CO .21
>
> Thanks
>
> Scott