ANY 05 JEEP G.CHEROKEE MECHANICS

Hard to say without seeing and troubleshooting it in person. Could be a number of things. When it doesn't run, lay underneath and beat the bottom of the gas tank with a rubber mallot close to where the pump is and have someone turn the key to ON position and see if the pump runs. Sometimes the shock of hitting the tank will "jump start" the pump...if that works then you need a new pump.