1999 Jeep Cherokee Sport 4.0L 6cyl

I had the same problem on my old Cherokee - I replaced the cam and crank sensor and never had the problem again

Before you go crazy spending all kinds of money. Take a plug wire loose from the plug, insert a long screwdriver into the spark plug wire end, then using the well insulated screwdriver handle, hold the bare metal shaft about 3/4" from a solid metallic ground and have a partner turn the key on and crank the engine (it's okay for the engine to start and run) and observe the condition of the spark from the screwdriver to the ground. If it seems weak and barely clearing 1/4" to 1/2" of air, then consider replacing the coil prior to replacing anything else. About $45 and 15 minutes to change sure beats replacing about $1500 worth of all the other possible parts that could go bad. Of course, if yoiurs is 1996 and newer, you will be able to get detailed readings from an enhanced ODB2 reader. The 1993 and earlier year modell ODB1 readings are not detailed enough to detect coil malfunctions. I struggled with non-start on my 1993 ZJ and spent a ton of money on it, even took it to Hotye Jeep in Sherman, TX and they ripped me off for $300 and never found a thing wrong with it but never refunded my money either. Good luck!