Renix 4.0 Part Throttle Miss and Refuses to Start

My 1990 MJ (4.0, 5 speed, 4WD) is quite a character. I've been working on her pretty steady since I got her and, thus far, she's refused to start twice on me. Both times I've ultimately managed to get her running but it seemed to be a combination of luck and patience.
The first time she refused to start (cranks fine, just won't start) I surmised it was probably the pickup in the distributor so, when I tuned her up, I replaced the distributor ($3 more than for the sensor alone). I was surprised that plugs, wires, cap, rotor, distributor, and fuel filter didn't have much effect on my part throttle miss. The miss is in 3rd and 4th gear between 25-60% throttle. In any event I didn't think I'd have any more refusals to start.
Tonight I left work and, once again, she would crank but refused to turn over. The fuel pump was coming on, there was plenty of gas when I pushed the Schrader valve in, and the air filter is new. I don't know if I had spark because I didn't have a second body to crank while I held the plug wire near the block.
If this follows the pattern that's beginning to emerge she'll start fine for the next 2-3 weeks and then refuse once again. At this point my only thoughts are the ignition coil and/or module, espec since I have a part throttle miss. Anything I'm missing here?

Check CKP, rear of the engine with a 3-pin conenctor. When it doesnt start, disconnect and re-connect and if it starts after.. thats your cause. Have you replaced the coil? The way Renix system works is it uses the signal from the CKP, and the ECM needs to see 300rpm or more for it to start. With a failing/failed CKP this can cause a no start problem.

I haven't replaced the coil or module yet b/c they're surprisingly expensive ($50 & $100 respectively). I was going to make a list of what it is or could be and see what I can pick up at the junkyard on Sat.
I haven't tried the CKP but, if I remember the FSM correctly it's supposed to be somewhere around 200 ohms hot. I did check the intake air temp sensor and coolant temp sensor and resistance on both seems fine.

1987Comanche said:

I haven't replaced the coil or module yet b/c they're surprisingly expensive ($50 & $100 respectively). I was going to make a list of what it is or could be and see what I can pick up at the junkyard on Sat.
I haven't tried the CKP but, if I remember the FSM correctly it's supposed to be somewhere around 200 ohms hot. I did check the intake air temp sensor and coolant temp sensor and resistance on both seems fine.

Click to expand...

200 +/- 75 ohms or 275 ~ 125 ohms.