I have a 2004 Tahoe with the 5.3 and 151,000 miles. When I get it up to about 70 mph, accelerating the engine will bog down and eventually shut down. I can wait for a minute and it will start up and go again for about 6 more miles and do the same thing. I have noticed it does this at under 1/2 tank of gas. Once it is full it does fine. Could this be fuel pump or the ECM.

 

When was the fuel filter last replaced? It may be clogged and making the fuel pump work even harder.