Bad Fuel pressure regulator?
 

My jeep wont start when its cold but once its been running at operating temp it will start but then once it cools down its a no go. I replaced the coolant temp sensor and the fuel filter then I checked my fuel pressure and it was at 40? I didn't think it was supposed to be that high but Im not sure I just want my sexj to run without using ether. Any help or bit of info you guys can give me would be great thanks guys!

When my regulator started going bad I could turn the key to on but not start, hear the fuel pump prime, and I could tap on the regulator with something like the handle of a screwdriver and I could hear the fuel pump prime again after a few taps. Plus it never hurts to change old vacuum connectors and boots when u can. In fact since idid the vac boots a haven't had a prob since but temp never made a difference in my case.

Always post the year of your XJ when you start a thread.

By your name, if this is a 93, you should have 31 psi at idle. Then disconnect the vacuum line leading to the fuel pressure regulator and the pressure should jump to approximately 39 psi.

Be sure that the vacuum line leading to the regulator is pulling good vacuum and is not wet with raw fuel, which would mean that you have a ruptured diaphragm in the regulator.