One problem related to manifold/header/muffler/tail pipe has been reported for the 2007 Chevrolet Trailblazer. The most recently reported issues are listed below.
My 2007 Trailblazer ss has a manifold exhaust leak. The bolts are broken on the left front of the head and back bolt of the head on both sides. We are getting exhaust gas in to the inside of the truck. This could cause carbon monoxide poisoning. To the driver in the vehicle, this is very serious condition.