Hyundai Repair: 2001 Accent No Idle, valve head, trouble code

Question
2001 Accent 1.6 L DOHC.  Recent valve & head repair.  developed
rough idle after put back together.  found crack in manifold next to
O2 sensor.  replaced sensor with new one and replaced manifold
from wrecked model.   now it will not idle at all!  can you help?  
Thanks - Kevin

Answer
Is it misfiring?  If so you need to check the ignition system and the compression.  If the compression in one or more cylinders is low, you'll need to recheck the engine work that was done.  Is the check engine lamp on?  If so, the stored trouble code(s) will likely be helpful.  Was the camshaft timed correctly during reinstallation?

If you can give me more information about how the engine is running, I may be able to provide some more specific info.