general problems of the 1998 Chevrolet Cavalier

In August of 2002 I had the front right anti-lock sensor for my 1998 chevy Cavalier replaced. Within nine months, may 2003, I had to have the same sensor replaced. Now it is may of 2004 and my dealership is telling me that I need the same sensor replaced. My thinking is that they should of found something after the second time I brought it in. Since the 3 years or 36,000 mile warranty is done I have to rely on the parts warranty, which does not help me if I have to replace it every year. Three same exact sensors replaced less that two years is senseless.