I have a 96 Legacy with 80k miles, the problem is the ABS light occassionally will come on, and stay on unless I turn off the engine, in which case it'll go off. This happens when I hit big bumps, then once it's on the brakes feel almost sponge-like. I just had new brakes & rotors put on and no luck. I hate taking it to the dealer, but if anybody has any idea what I need to do here I'd appreciate it.

Start by flushing the old brake fluid out.