The timing chain has stretched and the cam carriers have shattered after only 72,000 miles. What could cause this? I have found out that the car was mapped/chipped by the previous owner. Have no idea about cars. PLEASE HELP. The car needs a new engine. If the re mapping caused this, then I'm hoping the car dealer (who didn't notify me it had been re mapped when I bought it 7 months ago) will be liable for the costs.