I replaced the fuel pump in my 93 Grand Prix 3.1. It ran fine after the pump was installed. It set for a couple of months after that. I started it and drove it around for about 20 minutes. I parked it again for 3 weeks, the battery was dead when I tried to start it again. I jumped it off and it idled great for 20 or 30 minutes and then died. Now it won't start at all. It tries to turn over but doesn't start and it backfires. I can hear the fuel pump come on when the key is turned on and I put more gas in it to make sure it wasn't out.