Subaru Idle Update...

[anthony25]

following on from my previous thread regarding my friends subaru idle/hunting issue......well ive decided to order a new maff sensor..should arrive tuesday.....so been having a nose around the car in the meantime..and came across this...i left the battery off overnight..connected it today...started car...idling just under 2000rpm from cold...once engine is warm car settles..its trying idle normal then dropping etc then back up...i removed the oil filler cap and to my amazement..idle needle is sitting nice no hunting etc...i have a little bit of blow by from oil hole which ive been told is completely normal as long as when you put your hand over the hole its not building up any pressure which it isnt...no smoke coming from the hole or the oil check neck or exhaust....my maff arrives in a few days like i said...but i took the car for a drive aswell and the hesitation seem to have gone..hardly noticeable at all...im wondering if there is a blockage in a breather pipe of some sort..obviously worth carrying on investigating while im waiting....as soon as the oil cap is put back on..the idle starts playing up again..althoigh since the batterys been off the whole problem doesent seem anywhere near as bad....

[tonyav]

By disconnecting the battery you have rebooted the ECU back to factory setting.

[anthony25]

yes tony true....but whats the issue regarding cap?

[tonyav]

Don't know for sure what the issue is with the cap, does sound as though it is pressure related though.

[anthony25]

maff sensor fixed the issue...running spot on idling perfect....good refrence for anyone else with similar problems.....thanks tony for your response etc....common on subarus cause all kinds of issues and engine ecu codes but got their in the end,,,,,