I have a 1997 jeep cherokee laredo It cranks over but will not start. After 3 days of trying I went out turn the key and the jeep started with no problem, turned it off and did the same thing cranked but wouldn't start. I was told it was the crank shaft sensor from some one who has owned many jeeps. Does this sound like the correct solution.

Yes, try replacing the Crankshaft Position Sensor. Easy job. After all the cranking, I would also remove and fully charge the battery. Ensure you only use the same Champion spark plugs that came in the vehicle--replace them if they are over 3 years old.