So how did this turn out? On the edge of my seat with this thread!

Boy I thought I had posted the results; sorry. Replaced the purge cannister solenoid and then reset the codes (although that seems more difficult than I expected). I had to pull the most complicated method of doing it off Josh's 'site but it finally reset the codes. I had added a can of seafoam to the last tankful of gas that I installed before replacing the solenoid. The more I ran the car the better it got. I now have 2500 miles on the engine I installed and haven't seen a CEL since the re-set. The high idle/slow return has been gone now for four weeks. I get 22/23 mpg and the new engine doesn't lose a drop of oil in 2000 miles when I last changed it. I'm fortunate to have gotten such a good engine; looks like it will be a keeper!

I had a simiar problem in my 2000 2.2L Outback Sport. There was actually an ECU a flash update available to fix a high idle glitch. Apparently it was a problem in all 2.2s in 2000. You should call your local dealer and see if there is an update for yours. It worked for me.

 

I got all the same types of codes before the flash and the diagnostics turned back no problems with any of the sensors. My problem was compunded however by a bad cat. They replaced the cat under warranty.

 

So thats my 2 cents before you go replacing expensive sensors, try a free phone call to cover all the bases.

P.S. I have not had a CEL since the CAT replacement and reflash.