I have a 1999 Blazer that ONLY when you hit 60MPH or over and when you drive up hills it will stutter like its out of gas. Like it wants to die. Now it doesn't do it when Im at a stand still or any other time. Just when I'm driving fast speeds. If anyone has any ideas, please let me know. Thanks ahead of time!

Just guessing here but it sounds like a fuel pump , fuel filter , or gas tank problem . Just my :2cents:

I have to agree. Our 97 ran a month on a fuel pump going out. Then one day it just quit & the tow truck arrived to get it home.

FUel pressure issue for sure, it cannot get the volume it needs. Time for a fuel pressure checkup.