Ok, My fuel pump in my 77 280z is acting weird.... when I go to start the car when it hasnt ran in 4-5 hrs the fuel pump wont come on... but here is the kicker.. leave the key in the on position for 3-5min and the fuel pump will start. have taken a voltmeter to the wires and sure enough Zero volts until 3-5 min then instantly 11.9v I am very confused i do not touch anything I sit perfectly still. anyhelp would be greatly appreciated.