I'm having issues with this code as well, however, my wife's Subie is an automatic 1997 Outback. We bought it not running worth a crap, they thought it had a blown headgasket, but it was just the timing belt. Reinstalled the belt, pulleys, and tensioner, checked compression.
Now, when I turn it on, it will run at about 2000rpm for a minute or two, then drop down to about 1000rpm, pop a CEL code, and then runs like crap. Sometimes the engine shakes, like it's running on 2 or 3 cylinders, other times just runs really rough. I've replaced plugs, wires, and checked the coil pack. I've tried starting it just with 1 and 2 or just 3 and 4, and will run soso with either set of cylinders.
I'm baffled. I'm going to take apart the intake assembly and see if anything is gunky and/or not running ok and will post back. The only thing I can think of is the IAC.