Okay so heres the deal. I have a 01 XJ with a 98 engine I put in it. So after I got it going to about 55MPH it will eventually stop accelerating even when I have the pedal pushed all the way down. It will then eventually sputter to a stop and most of the time completely die, but sometimes stay running, but just bareley and it will sputter. When it dies I can start it right back up and drive for a few minutes again before it does it again.
I have replaced the following prior to this happening as I rebuilt the jeep last fall.
Fuel Pump
Alternator
Battery (Did a load test as of today and it is good)
I replaced and gapped the sparked plugs today.
Replaced the TPS.
I do have a low Idle of about 500 after it warms up and its slightly higher now after I replaced TPS and plugs.So maybe 550-600.
When this first started to happen my jeeps check engine light did blink multiple times, but did not stay on. Now it doesnt come on at all when the jeep stalls. The battery did die because I have a parasitic draw on the jeep and didn't drive it for a month so I did not get a chance to attempt to check a code.
I am currently thinking of replacing the Crank Position sensor, but that is expensive and a pain in the ***. Also I might test the Fuel pressure, but I did replace the fuel pump a year ago so I dont think that would be the issue.
Any Advice would be much appreciated on what the issue might be!!!!!

Did some tests on the Coil Pack and CPS and they came up good.

Changed the CPS anyway just to see if anything changed and it still died.

I'm going to test fuel pressure to see what comes up and drop my gas tank to inspect fuel pump whether or not I get a good or bad pressure reading.

 

Replaced Fuel Pump, was no big deal since it was under warranty.
Replaced Coolant Temp Sensor.
Still nothing.
Possibly ECU/ECM or 02 sensors?

 

Replacing parts without testing are we? Any codes?

 

I would have tried doing a fuel pressure test however my fuel rail does not have a schrader valve. So i went with a hunch. Didnt work out thought lol
No codes at all unfortunately...