Add me to the list. Happened to me yesterday on expressway. Only warning was that it happened earlier yesterday morning at idle and went away. What a shock. Montytx, I agree with you completely about safety. There is a law suit. Same thing happened to a lady, I believe in TX, and she couldn't stop and hit another car. This is a big problem and it appears GM knows all about it, but I don't see any recall. I found this info using google search. There is also a GM TB on the fix, which some claim is a misleading repair to dodge the real issue.