I need help ASAP

I got a 91 Camaro Rs V6, I've ran into a problem. I can get it to start and run but after its been running for awhile it starts to wanna shut off and it will if i let it run any longer. it will make a ruff sound and when i hit the gas it will start to sputter well it goes up and then when i go to move it it'll just shut off, then it becomes hard to start it back up, but it only does this after its been ran for about 10 mins. for the frist 10 mins it runs fine. people have told me it sounds like it isnt geting gas but you can smell the gas and hear the pump kick on. I did find a hole in the brake line and its leaking bake fluid, but i dont know if that would make it run like that? I just put on a new alternator. please help!

Check the condition of the spark cold versus "hot". Sounds like an ignition system problem.