my car's check engine light is on,when i start the car its off but ill drive it a half a mile,it will come on and wont shut off,it idles like it wants to shut off when im at a stand still.sometime it feels like its losing power,when i take off,when i shut it off,like to go to the store,ill come back and have to start it about three time(give it alittle gas) to get it idled up=/ i just got a main relay it helped it alittle.im in need of a cataltyic,i dont think that would make the car run like it does.please help thanks jessica

Optional Information:
1992 Honda civic 1.5

Already Tried:
main relay