I am having VERY similar problems with my 2003 and it is in the shop for the 3rd time this month. Subaru still can't pinpoint the issue and it is about to drive me crazy. I love my car and it has never given me problems... until now. It has to be electrical. But is it a short? Wiring gone bad? Computer issue?
It all started with a random check engine light. Then two weeks later it popped back up. Then it was check engine and ABS. They never stayed on long. One day I started my car and my whole dash lit up (check engine, ABS, turn signals, seatbelt light, etc.), some sort of "growling/buzzing" coming from the glove compartment area and I couldn't get the car out of gear. Turned off the car, started it again and all was fine. Then a few weeks later it happened while driving. All the lights, plus my trip meter going to zero and the car saying I had a full tank of gas. The spedometer and RPM needles didn't work. After a minute of driving or so, everything seemed to reset itself. Spedometer going "0" to "40" in an instant. This happened twice before getting it to Subaru and then two more times (with about half the lights lighting up) after I got the car back and they said the battery cable was loose. Computer said the car was fine. No major codes. (tail light doesn't count
Subaru hooked it up to a monitor and drive it over 100 miles the second time they had it. The car didn't act up with them so they couldn't find what was wrong. (Like a kid knowing they are going to the doctor, I swear...)
I get the car back and it happens again.
Now, it is in the shop and I'm worried about how extensive (and expensive!) this could possibly be.
So, if your mechanic figures it out, will you let me know? Thanks!