AOS Question
 

When I read that an AOS "goes out" or needs replacing, I'm somewhat confused. What exactly goes bad on it. I can understand the bellows tube cracking, but since there are no moving parts (that I know of) and no mechanical devices inside, what makes them go bad. Would not a thorough cleaning and a replacement of the bellows tube restore it to like new condition?
I'm sure a lack of understanding is my problem....

I'm having bad idle control problems. I've cleaned the throttle body, MAF, and idle air control valve, but it still hunts for proper idle and frequently dies when the clutch is pushed in. I have to feather it down to 1000 rpm or so before applying the clutch to keep it from dying, and even this doesn't work every time. I figure the AOS is next on the list, but I need to understand what can be bad on it. Thanks

Maf
 

with the engine running "tap" on the MAF with a screw driver. If it changes the idle you need to replace the MAF. "hunting" is typical of a bad MAF.

Let us know if you figure it out.

Good luck

The AOS is basically an oil distillery.
It has to extract (distill) oil from the crankcase vent.
It does so with a thin membrane which is what generally fails (rips).
Once that membrane rips, there will be an idle leak, just as if you open the oil fill tube or remove the dipstick.
If you have cleaned the idle control valve and the throttle body, I bet that a new, properly installed AOS will cure your idle hunting issues.
Happy Boxstering,
Pedro