Please help!!!!
 

I recently bought a 2000 honda civic dx. It has the 1.6L Sohc. The tranny has been swapped from auto to a manual. Have no idea what the tranny came out of. The issue is when i put it into neutral or push in on the clutch the idle is very high. Not sure exactly how high because there's no tach. Im guessing 2500? Any ideas or suggestions? One of my thoughts is the pcm should be changed to one from a manual. Idk if it was changed but i doubt it was. Its throwing codes saying that transmision gear position unknown n things to do with the transmission. So I'm assuming its communicating woth the transmission the way it should. Im lost