When I get into the car I turn the ignition switch to the on position and cannot hear the fuel pump turn on, then try to start the car and it cranks but wont run. Then I turn the key off and on again and I can hear the fuel pump kick on then I crank it and it starts and runs, but then somtimes as I am driving down the road at 50 mph it just stops running i pull over and put it into neutral and somtimes it starts and somtimes it doesnt. I have replaced the fuel Pump Relay. Any Wisdom... Thank You