Just replaced the intake manifold on my Del Sol, now bellows white smoke?

Ok so i just replaced my intake manifold with a ported one, that didnt work out so i put the old one back on. I'm pretty sure i connected everything right but now it smokes white... real bad out the exhaust. oh and my idle revs up and down, but that was goin on before a did anything to it, i thought changing the man. would fix it. HELP! thanks