For 1990-2009 cars

Cause | Correction
--- | ---
Worn, damaged or stuck valve, carbon on the valve stem or valve seat. |

1. Inspect the valves.
2. Inspect the valve guides.
3. Repair or replace damaged components as required.

Worn, damaged or dirty valve lifter. |

1. Inspect the valve lifters.
2. Inspect the camshaft.
3. Repair or replace damaged components as required.

Worn or damaged camshaft lobe. |

1. Inspect the camshaft.
2. Inspect the valve lifters.
3. Repair or replace damaged components as required.

Worn, damaged or loose timing belt and sprockets. |

1. Inspect the timing belt and sprockets.
2. Repair or replace damaged components as required.