One problem related to manifold/header/muffler/tail pipe has been reported for the 2005 Cadillac STS. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2005 Cadillac STS based on all problems reported for the 2005 STS.
Went outside to drive the car begin to drive off as I was driving a big ball of smoke came out the tail pipe and sounded as if something broke and the car shut off. The car would not re start.