ABS problems

ok heres the story, i got a 95 gsr and my abs light turns on right when i start my engine. its been going on for a few months now. AND, i get this buzzing sound for one second, and engine gets weak and hesitates, then when buzzing sound is gone, engine gets normal again. this happens every few minutes. can someone tell me if they experienced this or what the problem is??

have you checked your abs fluid level ?

checked it, its over max. what else should i check? just looked at clutch and brake fluid too, it's as dark as oil. gonna replace that too.