Another no start problem (Not NSS)

So I tried searching for about an hour and came up with essentially nothing that helped me (searching for "no start" comes up with almost every post!). The problem I have is this: up until yesterday, my XJ ran just fine. This morning I went out to start it and it just cranks and cranks. I can hear the fuel pump engaging and it sounds like it's trying to turn-over, but just can't. I recently (bout 1 month ago) replaced both the starter and alternator. The spark plugs have been replaced about 4 months ago now. After I let it sit for about 6 hours (figured I'd flooded it pretty good anyhow), I tried to start it again. It cranked up and began to start, then just kept cranking. When I say began to start, I mean it actually began turning over, but then just went back to dry cranking. Does anyone have any suggestions up front before I begin replacing stuff left and right?

Specs: '92 XJ, 4.0L, I6, NP231, Automatic, AW4, bout 240,000 miles on it.

Check your CPS.

Try moving the wiring harness to the CPS. My 90 did the same thing. I replaced the CPS and everything was fine for a few days and lo and behold it did the same thing! What the problem was --it was the wiring harness where it goes over the intake/exhaust manifold. Over the years the wiring got kinda cooked inside. I cut it and spliced it together and it's fine. Now I.ve got an extra CPS!! Try the wiggle test it might work.. LOL

Well I went out this morning to poke around under the hood and see what I could come up with. I made another attempt at starting it, and amazingly it started! It started really rough and I had to feather the gas to keep it running. After about 1 minute of this, it idled just fine. I took it out today and have started it numerous times, and it hasn't given me one bit of trouble. Could condensation in the distributor cap be a possibility? I'll see what happens tomorrow after it has sat for a long period of time again.