One problem related to engine knocking noise has been reported for the 2007 Chevrolet Trailblazer. The most recently reported issues are listed below.
The Trailblazer died when my wife and children was sitting at a red light and when she started it back the motor was making a loud knocking noise. She pulled it to the side of the road and called a tow truck and had it towed into a garage. The mechanic said that the engine was shot. There was no indication anything was wrong when it happened all the gauges were showing everything to be good there was no noise in engine or any warning lamps lit up on the dash. We had the oil changed just 2-3 weeks ago. We have only had the vehicle for 8 months. Also, the driver side window switch has been acting up when you press the switch to put down the window it will not go into automatic down.