CUSTOMER CONCERN The engine rattles during startup, misfires on all three bank-2 cylinders, and stores DTC P0021. CAUSE Camshaft timing was incorrect from a failed timing chain; a supporting confirmed report also documents worn guides and a camshaft actuator. CORRECTION Remove and replace the failed timing chain and related worn timing components, set camshaft timing to specification, clear DTC P0021 and the bank-2 misfire faults, and verify quiet startup and correct engine o