while watching the datastream, does the cam and crank say there are in sync, it will say sync "YES" or Sync "NO"
and have you double checked the timing mark yet? was it doing it before it came in?
If it idle better when you remove the line, then it is running rich, what does the coolant temp sensor read on the datastream?
If the old plugs were black, then its running rich, have you driven this yet? is there a lack of power?