thoughts?

[RedStage]

experiencing an odd surge/vibration at idle...put the car in neutral and it dies down. Been like this since I bought it. 121,000 miles on it. 2003 with an auto transmission.

sound like anything or is this normal? Took it to subaru once for it, they didn't find anything odd...

[w.rohr]

I had something similar and checked the air filter and it was all clogged, after I replace it the problem mostly went away. Shortly after I got a code for bad o2 sensor and replaced it now no surging or rough idle and the o2 solved problem of low power between 1k and 2k rpm. May not be your problem but the filter only takes a min to check.

[RedStage]

thanks, did a bit more online research into the problem and possible causes

- PCV valve
- Alternator
- Clogged Throttle Body
- Plugs and wires
- CV axle
- Transmission mounts

these have all been associated with the rough idle at a stop...

Just did plugs and wires so that shouldn't be it.
Going to have to check CV axles and transmission mounts as those see to be primary culprits....

[anarchy1024]

Does the problem happen when idling in gear with the brake off (i.e. crawling around a parking lot), or only when completely stopped (i.e. at a red light)? If it's when stopped, I don't think it's the CV joints/axles... I guess it could be the transmission mounts, but I would think there'd be other problems if that was the case. Does the engine show those symptoms when in neutral, but with additional load (headlights / brake lights / hazard lights on, A/C compressor on, cabin fan on full, turning the steering wheel, all at the same time)? If so, the transmission is likely not the problem.

This article on PCV values seems pretty good, albeit generic: http://www.agcoauto.com/content/news/p2_articleid/197