I have recently started having a cold idle problem.
This is the problem:

Start car from cold and dose it cold start bit 1400rpm then slowly down but it goes way down to 300rpm and stays there.

Thought it might be the water temp sensor so have replaced that with a new one but no change.

I even adjusted the ICV and this is the part i can not get my head around if i adjust it (when at running temp) to say 900rpm and leave it there the next day do the cold start this and the idle is still 300rpm its seems no matter what i do with the idle control valve is wont increase the cold idle

But once the car is warm say 20 mins the car idles at 700rpm and the only problem I have then is rev hanging when stopping at junctions will hang at 1400rpm for a few secs then drop to 700rpm.

Things I have done
Changed MAF
Checked all lines for leaks
Water Temp sensor (ECU)
Changed ECU
O2 sensor replaced with NEW
Plugs changed and gapped right.
New coil packs

All in the hunt to solve my problems

Anything I could have missed or I can look at ?

 

Cleaned ICV? Dirt build-up in it will make it hang at certain positions. You need to remove the 4 (?) bolts to clean it thoroughly, not just the 2 screws on top.

 

I Have cleaned that with carb cleaner and it was taken off to do.

Could it be faulty even after been cleaned?

Is there a way to check ?

 

It is possible that it can still be faulty after cleaning - I have replaced 2 over my 4 years of Subaru ownership.

There's no way that I know to check it short of swapping it out.

 

well what I will do b 4 spending out some more money is take it off again and give it a long good soaking then a good clean with a tooth brush and go from there hopefully I might see some improvement or worsening which would be a good indicator that it is at fault.

 

Any luck with this mate? I'm having same problem with rev hanging! Annoying