What could be wrong with my car if it keeps stalling out while i am driving it and won't restart for a while afterward?

What could be wrong with my car if it keeps stalling out while i am driving it and won't restart for a while afterward?
well im driving a 95 pontiac grand prix SE with the 3.1L engin and what happend at first was i went out side one day to start it and it would crank but die right after and then i got it runing and it acted fine till i was going down the road one day after about 15 mins of drive time it decided it wanted to stall out the r.p.ms kep jumping up and down every time it went down the car would act like its tryin to shut off so i went to get it checked out and it wouldnt even comunicate with the mechanics computer that he pluged up to it so i kep driving it try to make money to send it to a dealer and it got to the point where it seemed like if i only gave it so much gas it ran fine but if i gave it to much it would cut off stayd like that for like 2 days then i parked it at my friends house and went out side to leave to go to work and and it would crank but every little bit of gas i gave it would kill it i looked at the coil packs it looks like only one of the spokes is rusted "weired" but it acts like it could be a fule pump or a fule filter what could be wrong with my car can anyone answer this