Subaru Idle/hesitation

[anthony25]

as stated above my friend owns this car and has had this fault the last few weeks...idling rough hesitating and so on...sometimes cutting out at junctions...the car is a 2000 reg subaru awd turbo,with baileys dump valve etc...he has no engine lights on and so on...he was advised the air maff sensor are very common on them...so hes unplugged the maff while engines warm and running and the car splutters and engine light comes on.plugs it back in engine running fine engine light off..which says to me its working...ive spoke to my uncle who owned one for 5 years and said the iscv..idle speed valve get gunked up and are very common and sounds like the issue here?....

[anthony25]

just to point out it doesnt do it from cold..only when warm...

[tonyav]

Yes it does sound like the idle speed valve is probably gunked up, remove it and soak it in some paraffin for a few hours.

[anthony25]

cheers tony...will this contribute to the hesitation and so on too....he said something about it being worse on high boost....im not a specialist by all means when it comes to scoobys lol

[tonyav]

I have had similar problems in the past with idle control valves, but it was on Vauxhalls two Carltons and a Calibra

[anthony25]

if it was due to gunk why not do it from cold?....or is that because the choke will be running from cold?..untill its warm

[tonyav]

It's because the ECU makes the air fuel ratio rich when starting up from cold.

[anthony25]

ok will get iscv cleaned and let you know

[tonyav]

I used fetch them off and soak them in paraffin for a few hours, iscv would be ok then for a month or two, then had to repeat soaking them again.
If when it is fetched of the Scooby Doo and been cleaned up then works ok, if it happens again after a bit of time then I would get a new iscv if I were him.

[anthony25]

spoke to subaru specialist today..was told to do plug 2 black connectors under the steering wheel in and get codes from the ecu heres the result.....

45-map sensor
23-maff sensor
31-throttle position sensor

was told the maff can cause the other 2 codes aswell...........cleaned maff today took it out..it felt loads better still a little hesitant but nothing like before.....altho the idle cutting out is still the same....im thinking of replacing the maff and see what happens..........im not sure if the tps can be cleaned as ive heard they are a bugger to remove and have to be reset again after fitment.....if true would a direct replacement have to be set to the car is it simply not battery off plug and play.........