Iave inserted the question and their answer: What component or system failed or malfunctioned, and is it available for inspection upon request? Lifter valve number six failed causing it to shatter and send pieces of it throughout the engine along with other debris into the cylinders. How was your safety or the safety of others put at risk? Vehicle had loud engine knock, pulsation of power, had to pull off on main highways due to loss of power over 400 miles away from home. Has the problem been reproduced or confirmed by a dealer or independent service center? Yes, engine was serviced by GM dealership in Baldwinsville, NY for over $8,500. Will attach copy of bill. Now is doing same thing, again. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? GM as stated above. Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? Check engine light flashed, traction control light came on.