1998 GMC Suburban When stopping good brakes until I almost

I have a 1998 GMC Suburban that is in great shape...I guess?? My problem is I have replaced the pads, rotors, and much more. However when I go to stop it acts normal until I almost stop then it is like real spongy and feels kinda like the brakes are giving out. I was told it is brakes in the lines so I had them bled and it still done it. Then I was told that it was tha ABS wheel speed sensors, so I replaced them but still have the same problem. I can take out the abs fuse and it stops normal, but when I put the fuse back in it continues to do the same thing. I don't know if the brakes were not bled properly or what. I called the mechanic back after he put on the sensors and he said for me to pull the fuse adn then put i back in again to reset the computer. I tried than and the same thing. Can someone please shed some light on this before I kill this mechanic!!!