Auto hesitates on start up . ?
Start with the basics. Is there a check engine light or any other lights on? Any other performance issue. By hesitates to you mean runs rough, or dies. What is the maintenance history, filters, plugs etc. Which engine?
The vast majority of Trailblazers had the 4.2 liter straight 6, although a few did have a V8
Where to start??
Start with a greater than 5 word, vague description of the problem you are experiencing and what may have been done to fix it so far. You reap what you sow…
To eliminate the hesitation on start up is easy. Don’t start it.