Just had the same thing happen to me. I never thought it could of been a plastic bag. I took it in for service and am waiting for a call back. The cabin filled with plastic burning fumes and there was smoke coming from the top left part of the engine.
2005 330i ZHP 6M (SOLD!) / 2006 X3 (SOLD!) / 2007 328xi (SOLD!) / 2011 328xi