This is a 94 chevy corsica with ABS and I am having brake problems.
When I need to stop quickly, the brakes always seem to work fine. Although, when I am braking very slowly, such as pulling into a parking space, there is a good chance the pedal will go to the floor and I have no brakes other than parking brake.

I replaced the master cylinder with the same results. Next rebled the system including the two bleeders on the ABS system. I was sure to bleed the new master cylinder before I put it on the vehicle. I am not loosing any fluid nor does the wheel cylinders or calipers appear to be leaking. I am suspecting something in the ABS but I'm not too knowledgable of the ABS system. Any advice would be greatly appreciated.

I am having the same problem with my 96'.......when I slowly press on the brakes..my rear brakes goes and my car skids...and my antilock kicks in.......i took it to a shop..they could not find any prob. with it, changed brake pads, cylinder....still same prob....checked abs system...nothing wrong......any advice.

I wil try to break down both at once.
GM has a bad habit of the wheel speed sensor going south. 1 of the 3 or 4 you car has.If you have a " bad reporting" wheel speed sensor the abs will drop out at a low speed and NOT trigger a code( trip the abs light) and the pedeal will feel low. If your ABS light is on YOU KNOW THE PROBLEM EXSISTS!
GM had a bad problem with the w/cyls. Rule of thumb is to swap out both rear whell cyls and "FLUSH" out both rear lines.Not just bleed them,get fresh new fluid out the bleders.

I am having the same problem with my 96'.......when I slowly press on the brakes..my rear brakes goes and my car skids...and my antilock kicks in.......i took it to a shop..they could not find any prob. with it, changed brake pads, cylinder....still same prob....checked abs system...nothing wrong......any advice.

If the parking brake cable is hanging up a bit, it can cause the rear brakes to apply much more than they should, they lock up. On my car, I left the hand brake on the first click and didn't realize it until I hit my brakes while going around a corner. Put me sideways pretty quick, my ABS never kicked on though.