Jeep Repair: jeep starting problems, crankshaft position sensor, bad crankshaft position sensor

Question
recently my wifes 89 cherokee 4.0 has been acting up when staring. it will keep turning over, but doesnt fire. we can keep trying until the battery runs down. then it would start the next day. now it just keep turning over fine, but still wont fire up. what should i do?

Answer
Given there are at least 100 possible reasons why the Jeep will not start, all the way from no fuel in the tank to a bad Crankshaft Position Sensor and everything in between, I would have a mechanic check it out starting with fuel delivery, moving on to spark and ignition, etc.