I have a 97 with 4.0L six. Every few days it will not start. Then a day or two later it starts just fine. When it won't start it is getting fuel but does not appear to be getting spark. I don't think it is the O2 sensor. This problem does not leave the check engine light on. Any advice as to where to look? I believe the possible culprits could be the coil, distributor, crank position sensor and cam position sensor. Anything I am forgetting? Anybody have a similar experience that can direct me to the issue?

When fording deep water, is it advisable to change the diff oil afterward each time? Will water get past the plug? Both diffs have a rubber plug.

 

Ok some older jeeps the shifter won't click the safety lock an you will have to push it an crack it at the same time mine did this

 

Maybe dont know if this might be it, but I have heard that if you keep getting mud and water up in the engine bay you might be getting mud and debri on the starter and its not allowing it to get a good connection. I know this happened to my buddies rig alot, he just flushed it with water and it started after a few cranks.