Engine hesitation or stutter

I have a 03 Trailblazer EXT. A couple of months ago, I was driving on the freeway and around 2K RPM and 50 MPH, I would get a slight stutter or hesitation from the engine. I took it to the dealership and they reprogrammed the computer and it seemed like it went away. Just yesterday, I had the same thing happen but it wasn't as noticeable prior to the reprogram. Has anyone had this issue before? Thanks.

I have a 03 Trailblazer EXT. A couple of months ago, I was driving on the freeway and around 2K RPM and 50 MPH, I would get a slight stutter or hesitation from the engine. I took it to the dealership and they reprogrammed the computer and it seemed like it went away. Just yesterday, I had the same thing happen but it wasn't as noticeable prior to the reprogram. Has anyone had this issue before? Thanks.

3 questions ,,
were you driving on hilly roads?

Were you using crusie?

did you have cargo of any type?

i have had this issue when driving to tennesee from iowa going through the mountains with cruise control on ,, at the crest of the hill it would "surge" and continue to do so as long as i was going down hill.

i had about 600 pounds of gear and luggage in the back end making it want to coast faster down hills and the motor was trying to hold a constant speed resulting in a surge type feeling ,, to fix this issue i changed my O2 sensor (manifold) and the problem went away.
joz