Back ground info:
2003 Outback sedan with 122K miles. Purchased used about 2k miles ago. Only obvious work is: New battery, alternator and serpentine belt. All fluid levels have remained stable. Using premium gasoline.
Problem:
Just last week I noticed that the idle speed would drop when the accelerator pedal was let up. It actually died twice maneuvering in a parking lot. With no throttle input at all it idles smoothly at about 700 RPM. When I got it home to look into the problem I thought that I might not be able to replicate it. I started the car after it had set overnight and I could not get it to lag or die. Gradually as the car warmed up the problem became more noticeable. At operating temperature I could reach underneath the accelerator cables on the passenger side of the throttle body and feather the tab that operates the throttle. Upon let off, the idle speed would sometimes drop for 2-3 seconds then return to around 700 RPM, and sometimes the engine would die before it could return to normal idle.
Several threads point to MAF. Is there a MAF on this intake? Where is it located. If this is not the issue, what else should I look at?
Codes read and cleared. All had to do with air and fuel intake stuff from starting and running it with all of the air intake duct work off. Runs like new now.