Coil wire is a great lead . When was the last tune up ? This could be a bad plug even , might work , just not well .
Give us the low down on what you know as been done to this jeep .
BTW , a simple test for the ignition would be , hose it down and then try to start it . Any hiccups , and you found your problem . Good ignitions can handle a good engine bay cleaning without issue , I pressure wash mine all the time . Double check all the wires for good contact at the plug and distributor cap . Spark jump could very well be your issue . Simple fits