Re: 2004 jeep grand cherokee 4.0
Will it also die when driving, or only when idling? Could you give the exact codes you where getting? Did you change the fuel pump for this problem, or was something else going on? Low fuel pressure can be caused by a faulty/clogged fuel filter/pressure regulator, but fuel pressure related problems will normally give problems during acceleration and higher rpm´s.
A faulty O2 sensor could make the fuel/air ratio too low and the engine will simply die. That could explain that it will run ok for the first 15 minutes (still in open loop mode and not using the O2 sensor(s) for fuel fine tuning) and gets the problem when it has warmed up (now in closed loop mode and using the O2 sensor input for fuel fine tuning).