i have a built gsr and is blowing white smoke out of the exhaust. when i take the headers off, ports 3 and 4 seems to have coolant in them and is clean with no black carbon residue. where as for ports 1 and 2 seems to be dry w/ minimal amounts of carbon. i recently changed my head gasket and is still smoking. i also notice that my idle is bounicing anywhere from 1000-1500. car doesn't overheat or anything. what could be the problem?