1998 jeep wrangler 2.5 motor

I have a 97 jeep wrangler that was built in November so I think the motor is a 98. ok the problem is after about 20 min of driving it acts like its chocking out and dies. after a few minuets it will start but just idle. when it is cooled off completely like the next day it will run for 20 min. or so and do it all over again. I have replaced the sensor under the distributor cap and the crankshaft sensor but it still dose it.
1998 Jeep Wrangler