I had idling issue and send for service center for subaru only.
After spend for est $1900 , change 2 pcs MAF sensor, oil, spark plug, gearbox oil, Diff. oil,
air filter, clean throttle body etc etc and end up tell me that I need to send for retune to slove
Before I do anything tuning myself, when I remove MAF sensor wire, there is engine light up but there is
no more idling problem, But when I put back the MAF sensor, within 5 ~ 10 min , the idling jump from 650 RPM to 1100 RPM. IF repeat by remove the MAF wire, the idling will stable.
My country temperture is 33 degree C.
No problem when cold start and after the engine warm, idling start to have issue.
I didn't find the right solution from the Internet.