What could be the causes for this car to die?

2000 lincoln continental v8. im thinking of buying this car. I just started it and it died. I turned the key again and it started. I drove it down the road at about 75mph and pulled over, turned it off and turned it back on and it started. I get out while it's running then get back in and put it into drive and gun it and slam on the brakes and it dies again. would could be the causes? vacuum leak, fuel pressure, electrical?