Looking for any reply that might help steer me in the right direction with this problem. The 03 Forester runs rough, skips, hesitates after it sits in the driveway overnight. Only does this until it warms up in the morning and then runs fine the rest of the day. I can leave it parked at work for 8 hours, get in, and it runs fine. Only after it sits overnight does it run rough in the morning. Could that be condensation in my gas tank?
Problem FIXED: I went to change the spark plugs and when I pulled the ignition cable out of #3 - part of the metal clip was still inside the spark plug well and still firmly attached to the plug. It had apparently come apart when the Subaru monkeys performed the last Level C or Level D service (they're the only people who would have had their hands on the spark plugs before I went in and Yes - I was very careful to pull the plug from the base and not yank on the wire itself). After I replaced the plugs and ingition cables the car runs like new.
Regarding the Pxxx numbers, I have had a P0420 for a couple years now. I performed the "$5.00 Fix" described in previous posts and have put about 500 miles on the car since then without the CEL coming back (and it passed emissions testing yesterday).
It can be found at: forums.evolutionm.net. I cannot post the link since my post-count on this board isn't high enough. Maybe a little later, I'll have eanough to pass muster and can post the entire link.