...and, I have a voltmeter at my disposal. I checked gps, seems to be functioning as my haynes manual says. What next.

 

x2 if everything else you listed didnt do it, then id look at the pump...

 

even if the CEL isnt on, that doesnt mean that there isnt a code that has stored in there waiting to be pulled by a code reader. i recently discovered this when we put a reader on and there were a coupla codes that were just sittin in there, not tripping the CEL, but that were helpful in diagnosing the prob...

 

I just put a NEW FUEL PUMP in the jeep on Monday no change, I just checked the TPS, and its good. All of the other parts listed have been installed since the last time it ran. It's none of those parts or something would change. Every single ignition component has been changed. I even have multiple ECMs. Nothing changes

 

i was looking back to check over the list of replaced parts... i mighta missed it, but what about o2 sensors- the downtream (bank 2) o2 sensor has a tendancy to go. if ya do one, do both and dont skimp on the quality (should be right around 100/ea. for the good 4-wire, heated ones)... idk, limited options as to what it could be... im in the same boat, though... it sucks... good luck!

 

jumped in late to this party but have you by chance in all your checking of parts did you make sure the dist. rotor is even turning or that it got put back in. (not that i have done that before) and i am not sure about this motor but could your timing chain have jumped enough to cuse a problem.

 

Now that you have a known good fuel pump in it, check all of your fuses. I'm talking the ones in the box under the hood. Crap, i didn't even think to have you check the fuel pump relay. Do you here the buzz from the fuel pump when you switch the key to "ON"? If you do the fuel pump is good and working. If not in that box under the hood there are other relays you can switch with the fuel pump relay that are the same exact one. Just long enough to see if it fixes it. there is also a main fuse that a bad fuel pump can pop. I think it's called Engine 1 or something like that. If that fuse is blown you will get no start at all.

 

I hear the buzz, plenty of fuel pressure. Spark at the end of the plug would mean the distributor is rotating. But it is rotating, due to the markings left by the spark on the inside of the termials in the distributor cap itself. The relays are good, I swapped all four of them in every combination possible. Checked all the fuses with a volt meter, 12v passes through all of them. None blown.

 

sounds like you and I are in the same boat. Lemme know if you figure out what it was.

 

Please tell me you got it figured out. I have the same thing. Good spark, good Fuel Pressure, new CPS (tried three) good fuses.

Your thread was exactly what I was just about to write. with one exception....
Mine will sometimes start! not often, but it does, so it's the intermittentness that is killing me.