87' bmw 325 bogs out

I just had my fuel pump and fuel filter replaced because the car would start but then right away bog out like it wouldnt idle so once it was replaced it ran fine for about a week and then when i turned it on again it did the same thing. i put some injector cleaner into the gas to help the carbon disperse, and the next day it started right up, but im just wondering why it would just happen all of a sudden then stop? I dont really want to get stranded somewhere. Any ideas?