Fuel + spark (plus compression and air) = start.
You need to determine what part of the above equation you are missing. Do not assume anything and don't throw parts at this. It's terribly inefficient and expensive.
Pull a spark plug. Keep it attached to the plug wire. Place the spark plug electrode near a good engine ground. Have a buddy crank the engine over while you watch. You are looking for a strong, BLUE, snapping spark. Yellow/orange/white indicates a weak spark which may not be strong enough to start the engine. If you have no spark, then a crankshaft position sensor is a possibility. But so is the ignition coil and a few other things.
IF spark checks out okay (and only if), then try introducing a small splash of gasoline or a shot of starting fluid into the intake. If the engine runs for a few seconds with this technique, you have clearly identified a "fuel delivery" problem.
The above two things are easy to do and will help you ISOLATE the root cause of your problem. Start there.
99 Cherokee, 4.0 AW4, NP242
Past Jeeps: 49 Willys, 81 Scrambler, 88 Comanche
Without "data", all you have is an opinion!