My zc won't remain at a constant idle. It will idle from 1200 to 800 up and down then back up then back down. Could it be the throttle position sensor? Anyone got some ideas?  

yes it is more then likely your tps and if that dosent fix it then reset your ecu with the new tps then it should be fine  

check ur map sen  

I have a 1991 honda civic with a newly rebuilt engine and now the car idles rough and stalls at intersections---spent alot of money and the repair shop says nothing is wrong.  The car is jerky to drive like the engine is not catching up to the gas pedal---on deceleration a big jump if the car is in gear.

Everything has been changed but the original intake manifold sensors?  I am totally lost---I realize this in not a new post but I can't figure out how to do that.