One more thing is the oil separator hoses behind the intake. One plugs in to the driver side valve cover and the hoses run back down behind the center behind the intake.

There are two of them around 3/4" OD. They are prone to crack and cause this as well. I had to replace mine. They will look great from the front but to the best of your ability check them on the bottom side and back. Esp where the one connects on the driver side valve cover.