1998 GMC Suburban Sputtering/Choking during accelleration

Engine Performance problem
1998 GMC Suburban V8 Two Wheel Drive Automatic 150k miles

This problem is blowing both the minds of dealership mechanics, no-name mechanics, and me. Long story short; When I start the vehicle it runs perfectly fine. After about 10 minutes of driving at 35+ mph it no longer lets me accelerate. When I press the gas, it either chokes out and jerks or nothing happens at all. When I pull over, turn the vehicle off, and start it up again immediatly, the problem is gone and it runs good again.

Sometimes it wont let me accelerate to 10mph, sometimes it wont happen until I am doing 50 and trying to accelerate to 60.

There is no SES light on. Every mechanic has told me that its in surprisingly great shape for its age. Yet, none of them can figure out the issue. Im trying to narrow it down before I go spending hundreds of dollar fixing one thing after another trying to find the issue.