what would cause the gas pump to malfunction in 99 firebird v6?

[michelle]

I have a 99 Firebird V6 and when I park on the hill it would not want to crank for a days and then it would be ok but now it will turn over but not start. Could my pump need to be replaced or could it be something else?
By the way I live on a hill

 

[melsg5]

How many miles on the car? Do you let the car run out of gas or very low so that the pump runs dry burning it out?