southbay

put a 98 ls1 into 02 z28,after many problems,finally got car running .IT runs great,then runs like crap,back a fourth.the p0412 is the last code I cant get rid of.I do know that the vacuum line that comes out with the ecm wires and goes to back of motor is broken.i have a plug in one end,but back of motor is not.I believe this is the problem.not sure what else it could be.can I just plug that line or does it need to be hook up.thanx howie