cant figure out whats wrong with my 2004?

i have a 2004 grand am with 147, 000 miles on. bought it used 7 months ago. It sputters
when i accelerate and when im slowing down. feels like the car is going to stall when i
come to a complete stop. When im going up hill, i get scared the car is going to stall
because sometimes it feels like it. Id like to get an idea of what the problem could be.