your clutch is toast...
Yeah im sure its your clutch/flywheel assembly. The same thing happened to me. Only it started with when i got up to like 5k rpms and then the rpms would drop to like 2k then start going. Finally it came to that id have to redline the car to get it to even budge. Im telling you that your cluch is like annihilated. Trust me!
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2002 WRX