You could just be running out of fuel.
A common fault is split or cracked fuel hose at the tank on the supply line. The pump sucks in air through the cracks as well as fuel and you end up with a lot of air coming into the float chamber.
Do you have a clear fuel filter or short length of clear hose that you can out in just before the 3 way filter? If you are seeing large bubbles it is time to drop the tank and have a look.
Another problem could be float levels in the carb, a low float level would cause problems at higher speed.
BagusJeep lives in Bali, the Land of Temples.
With a Jeep every prayer counts.
1981 CJ7 258ci - Bagusjeep
1984 CJ7 258ci - Puthijeep
1981 J20 258ci - Gladys
1995 Cherokee 4.0 - CHEROKEE