Recently my 2001 XJ began having issues consistently starting, it first happened a few months back and just recently it has become more consistent. It will crank over, fuel pressure is always at 45 psi. What I have noticed is that it seems to become labored at cranking the more I try. Here is the twist that I recently come across, when I press the gas pedal in and turn the ignition key only to get the fuel pump to purge then rotate the key off then on to turn the engine over it will either start or seems to want to start. Prior to trying this it would be very difficult to start. I was suspecting the Throttle Position Sensor so I replaced it and it didn't make much of a difference.