Sputtering while accelerating and goin up hills and idling?

My 1997 ford aspire sputters when idling, accelerating after taking off and while going up hills. It's fine once you get a little speed. What could cause this? It's not overheating. The check engine light is on. It is need of a tune up. It still gets good gas mileage. It's a 5 speed. It shifts no problem. Would a tune up fix it, or is it something with the fuel pump/filter/injector? Or the coils in the engine? There's no leaks with anything. It hasn't died yet. Idk what the rpm's are because it doesn't have that gauge. But I can tell they go up and down. Any help would be much appreciated.