start with the obvious.... any check engine light codes?
from there is to determine if this is an electrical issue or mechanical issue. using a fuel pressure gauge on the fuel rail can tel you if the fuel pump is not supplying enough fuel pressure. if thats fine, then check for vacumm leaks. how old is the jeep? older ones rely a lot on O2 sensor for the proper idle and if the sensor is bad, it can cause the described symptoms.
if all that is good, then do a compression test and a leakdown test. that will tell you if you have any mechanical issues with the engine.
cars only need air/fuel/spark.... if all are present is that they arent being used properly because a system is not working right