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View Full Version : uneven idle from cold



colfair
03-30-2012, 07:10 PM
Hi everyone and greetings from the UK ,

My problem seems to be the old uneveness/hesitation one and is like , When I start the car up from cold, it fires up ok but idles really roughly going from about 750rpm sometimes up to 1000rpm and sometimes down to below 500rpm. when i drive off it smooths out but if I stop at a junction it starts to become uneven again and often almost cuts out when I go to move off (which is just dandy if you're trying to get out of a busy intersection). The coolant temp comes up to normal in the usual time but this problem continues for maybe 15 minutes until the engine is really warmed up. It doesn't overheat and otherwise runs ok when fully warm. It is a real PITA though when cold . It's a MY2000 Legacy GX automatic 2.5 litre EJ251 engine UK spec model. Any ideas guys?

chuckthefuk
04-01-2012, 03:53 AM
Sounds like your Idle Air Control Valve or IACV...

Clean it..

http://denver2durangoviacoloradotrail.b ... ances.html (http://denver2durangoviacoloradotrail.blogspot.ca/2012/02/subaru-nuances.html)

https://sl-i.net/FORUM/images/imported/2012/04/iacvintake00obw3-1.jpg

https://sl-i.net/FORUM/images/imported/2012/04/IMG_0339JPG-2.jpg

https://sl-i.net/FORUM/images/imported/2012/04/IMG_0340JPG-2.jpg

Since you have the EJ251 your motor should run off a MAP sensor so the IACV style should match to the one I posted above. Alcohol and a Q-Tip. go nuts..

If your idle is still bad try replacing the sensor with a good working unit.. They tend to stick over time..
-Chuck

colfair
04-01-2012, 09:46 AM
wow thanks for the info, nice to have the pics as well as I'm a real newbie to Subarus. I will give it a try first thing on Monday and let you know what the outcome is, Many thanks again, Colin

chuckthefuk
04-01-2012, 09:52 AM
no problem.

And welcome to SLi.

Download your factory service manual here --> http://dl.dropbox.com/u/64502751/Subaru%20Liberty%201998-2003_FSM%20(sl-i.net).zip