try replacing the CPS anyway.

I had the exact same problem on my 1999 Cherokee 4.0L (auto transmission). I tested everything, including the crankshaft position sensor, and everything seemed to test good. After getting a new distributor and ignition coil we were stumped. Ended up retesting everything and tested the CPS the right way, tested bad. Replaced it and it started right up. Some Jeep people told me the difference in a test between a good and bad CPS is so slight its almost not worth testing them and should just be replaced.
So you may want to try a new one, even if you think it tested good.