1992 Pontiac Sunbird

Recently I had the speedometer head replaced and when the mechanic put it in he also reconnected my ABS. My ABS doesn't work properly and I had unplugged it at the firewall under the hood, but was wondering if there is another place I need to check for a connection? The reason I ask this is because after getting the car back, with the ABS hooked up, I was driving down the road and went to stop at a red light and something under the hood popped and my car started jerking and shaking and then my ABS light came on. I pulled off the road and again unplugged my ABS at the firewall, but now when I have traveled about 20 miles and my car is warmed up, every time I apply my brakes, my car starts sputtering and dies. The only way I can prevent this from happening is to downshift when coming to a stop, but I can never fully engage my brakes. Thanks for the help.
January 23, 2007.

Have the computer scanned for codes. This should give us a place to start. Usually the ABS wont cause the engine to stall.

Jan 23, 2007.