Hi everyone, I need some help. About 3 days ago my tire got pretty low so I filled it up with one of those tire sealers in a can deal. Came out yesterday morning to find my tire completely flat and a wet spot on the ground around the tire (I guess it was the stuff from the fix-a-flat). I went ahead and put on the spare tire started driving then less than a minute later the ABS light came on. Since yesterday morning it has been coming off and on. I will start the car and sometimes it turns off only to turn on a few minutes later, and other times it just stays on for ever. A couple times it doesn't come on for a while and then, Bam! there it is. Any one have any ideas what it could be and how i can check it?

P.S. Car is a 98 SVT with 72K miles.