i have this same problem, im gonna go ahead and check my pcv valve also and see what happens. ive gotten throttle bodies, map sensors, iac valves out of the junk yard and switched them out and nothing changed.....i even switched out my intake manifold for another one (a oem one of course) and nothing. im running all new hoses so im pretty sure theres no leak and i compared all my lines to my friends and their all the same. im gonna go ahead and check if it is the pcv and if it is ima be kicking myself for not checking it sooner.