I've notice that under a cool engine and when I go WOT i get a puff of smoke. I don't really notice it when its warmed up. My car is a 2004 Grand Prix and from what I can tell i still have the plastic gasket (i see black by the thermostat and not aluminum.)
Its not a heavy cloud or anything but definitely not right. My coolant seemed low so I added some more. Oil doesnt have that foggy look to it so it must be small amounts that get burned up.
My buddy is going to replace the LIM gasket on Monday, but just want to confirm with everyone here that has had this happen.