As I start reading the post...I know this one. Before the second thread I said...I'll put money on it!!!
Get that plastic piece out QUICK, mine let go on the highway and spewed all the coolant all over the place on the second day I had the car. Had to tow and have buddy do it at his garage.
It'* a cheap repair, only thing is it'll probably cost you more in time and skin swearing at how plastic can weld itself into an intake manifold then a mechanic would charge you. Most have a special tool to take those out. New part $5
00 Regal GS: All kinds of cool stuff.