While driving on a busy highway, the engine shut off completely. i pulled over to the shoulder and the dic indicated a throttle position sensor problem. i had it towed to a chevrolet dealer and they told me it was the ecm. i paid to have it fixed and sent an email (attached) to chevrolet customer assistance center requesting reimbursement.since the vehicle's mileage was only 39226 miles. i'm still pursuing reimbursement but want to file this complaint since this is a major safety problem to have vehicle totally shut down. interestingly, chevrolet was aware of a similar problem with the throttle position sensor and sent me a letter (attached) to extend the warranty.