My gasket eventually failed, and coolant was everywhere it shouldnt of been.
Had loss of power, top speed of about 50. Shop told me the plenum was warped and needed a new one (~$330 kit), also new plug, wires, oil, and coolant. Half cost went to parts, other half labor. Took them about 6 hrs.
Your talking the plenum gasket right' aside from it being it being warped,
I know when my car overheated I could not go over 50, then it died on the freeway. I can get a new UIM plenum for 137.00 over here in seattle, wa. and fix it myself, just hope thats all it needs.