When cam phasers go bad, it can cause various engine problems and damage. Signs that cam phasers are faulty include engine noise, decreased power, worse gas mileage, and check engine light illumination. Cam phasers control valve timing and can fail due to issues like low oil pressure, worn gears, or electrical problems. While cam phasers can sometimes be repaired by cleaning or replacing components, they often must be replaced. Diagnosing the specific cause of failure and performing the right repair is necessary to fix cam phaser issues.