One problem related to engine shut off without warning has been reported for the 2003 Chevrolet Trailblazer. The most recently reported issues are listed below.
While driving from work I stopped at a red light and the Trailblazers rpm dropped down and the truck shut off in traffic. But all the lights were on. I had to restart the truck and it crank up. Three weeks later I was pulling up to a gas station and pressed on the brakes to stop and the truck cut off (same experience). Yesterday I was driving in 5 o'clock traffic and pressed on the brakes and it shut off again.