Subaru Repair: Engine stays on hig revs on acceleration, throttle position sensor, communication gap

Question
I have a manual Outback yr2000 model with about 200K km.  Problem is, and appears to becoming worse, when engine is cold, when I accelerate above 2800rpm, engine stays on those revs until loading pulls it down then it will settle on usual idle.  Once engine is warm, all is okay.  But, I feel engine is rather gutless on accelerating until near 3000rpm, then is very good.  Another issue I noticed, if driving down a hill, the engine will not break the car speed until, again over 3000rpm.  I have been leaning towards a Throttle Position sensor problem.  Any other ideas?

Answer
Really needs to diagnosed.But may be as simple as dirty/sticky throttle plates for the sluggish idle situation and the other could be a restricted fuel filter for the sluggish engine performance.Yes it could also be a throttle position sensor and doing a sweep test would verify or rule out.But it is hard to diagnose certain symptoms over the Internet as there is always a communication gap with the complete understanding of the cars complete sypmtoms.There is a long list of things i would check to do a complete analyisis.I do hope that helps

Justin
All Wheel Drive Auto