Trac Off light in a 2001 Cavaleir

I have a 2001 Cavaleir. The Trac light has only come on three times. The first time it came on I was going up a hill slow and it came on then once I got to the top of the hill the car shut off. The second
time it came on I was at a stop light and then when I stepped on the gas pedal the car was real jerky. I pulled over and turned my car off and turned it back on, the light was off but when I put it in Drive (i have a automatic) it made a dull thud sound. The car drove ok after the the thud sound but Im just really worried. If anyone could help
Posted using the interface, at author's request
Articles individually checked for conformance to usenet standards
  Click to see the full signature.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.