I have a 2000 mustang gt. When i try to start the car it will try to turn over but will not start. when i jump the car it starts right up and runs fine (took it on a 45 mins drive). As soon as I turn the car off and try to restart it, will not start back up. I just replace the fuel pump and I had the battery checked right before that and the people at the auto place said it was good still. Any ideas where I could start looking for the problem? Thanks.