Ok, I searched the crap out of the web and on CF.

I have a 99 Xj with a crank issue. In the morning when it is cold, or even damp when I turn the key I get all power, I can hear the relay click under the dash, but it won't crank, when I retry a few times it will finally crank. After it has warmed up it will always turn over every time. When i let it sit for hours it may or may not crank depending on solar alignment and if the moon and stars are all in sync. Would this be the starter solenoid or the NSS most likely??? It is annoying, that much I know.

 

Try the crank sensor

 

I am on my way out to the garage to clean all of the cables, possibly pull the NSS and clean it out internally, I will also check the CPS voltage too. I doubt it is the ignition switch, it's never anything easy.... Will follow up.