Usually the number one cause of these codes is the pcv elbow coming from the back of the lower intake(Turkey pan) up to the upper plenum, check out the turkey pan fix in here, it deletes the hose with a plug, or if you have access, do like i did until i have time to do it, pull the elbow off replace with a good grade fuel hose and plug it with a bolt that fits tightly in it. Hope this helps you.