My recently acquired 03 legacy wagon has a strange issue. When I first start out on a trip, the clutch lets out normally and the car goes from dead stop to first smoothly. After she warms up, however, coming to a stop light the car wants to stall when I let out the clutch. So I give it more gas than usual and she chatters into a roll. At first I thought it was just me needing to get used to this particular vehicle, but now I'm certain that's not the problem. I've driven subies for over 12 years now, so I'm pretty comfortable with them.
When I first got the vehicle, it did this even on first start, but replacing a clogged air filter fixed that. However, now it seems to happen only after she has been running a while.
The engine does make a slight breathy diesel-like noise when accelerating under load, but I am leaning towards that being a small exhaust leak.
I checked the most accessible plug last night and it was pretty clean. I plan to change all the plugs/wires to new NGK's next week (iridiums).
Any other ideas or things I should look for?
Thanks in advance.