The camshaft is a shaft of your engine with one or more egg-shaped cams attached to it. As the camshaft spins, the cams open and close the intake and exhaust valves in sync with the motion of the piston. This is a critical job and can impact engine performance at different speeds. If the camshafts are worn or not spinning correctly, this can cause your engine to suffer. If your engine is idling roughly or accelerating poorly, ask your service advisor to take a look at the camshaft. A faulty camshaft is often a symptom of a much larger engine issue. The camshaft is linked to the timing belt or chain, as well as the crankshaft. Therefore replacement or repair is usually not simple. If your camshaft stops spinning because of a broken timing belt, the piston could hit the open valves. From a safety standpoint there is a slight risk, because a failing camshaft might cause you to stall. From an environmental point of view, there is low impact from a worn-out camshaft.