Good morning!
So I have been trying to diagnose this similar problem with a 96 Cherokee Sport I guess it is considered an XJ. Learning as I go.

Bought the Jeep a few years back and in the last 1.5-2 years i’ve had this issue. It will start right up cold. I’ll drive it anywhere from 15-30 minutes and either get to my destination and shut it off and it won’t start right back up or it will die on me.
After 30-45 min of sitting it will start right back up.
It will crank.

Doesn’t sputter, backfire, jerk, etc.

So I have replaced the following:
Distributor pick up coil
Distributor rotor (button)
Distributor cap (the inside was corroded and the center lead/spring fell out and was almost burnt through)
Fuel pump (only the pump not the entire assembly)
Fuel pump strainer
Inline fuel filter

I believe I tested all the relays correctly. I turned the Jeep on and let it sit for 25-30 min. Turned it off and it would not start. Swapped all the relays back and forth and tried to start and “nothing”.

I bought a cheap plug tester and tested each one and had strong spark for each one. It’s the cheap $8 one and the guy at autozone said as long as it’s consistent and not intermittent you should be good.
He tried telling me that you can buy one that if it’s one color it’s a fuel issue and if it’s another color it’s electrical. I think it was blue or red would determine one or the other.
Anyway.....

I will also note that the temp gauge typically reads 210. Now when I started it and let it sit and run for the 25-30 min it got up to the 230 range or so but never in the red.

When I search up Fuel Pressure Regulator it has it listed as Fuel Injector Pressure Regulator so I don’t think it’s on the fuel pump inside the tank.
These parts have all come from ORileys as well, but now I plan to purchase from Rock Auto is that is advised by you all.

I don’t really wanna take it to a mechanic cause it’s mainly my hunting vehicle and I also kind of like figuring this stuff out. THought I don’t wanna keep throwing money at it.
I think I’m about $200-300 in right now.

I’ve read many of the threads and this one seemed to be the most similar to what I have going on except for the yr model of Jeeps.

I did purchase the Harbor Freight fuel pressure gauge as well and was going to test like Briangbettes did.

 

You are posting on someone else's thread. Better off to start a new one.

 

Gotcha. Didn’t know if this was the best way to help explain what I had going on.