Why does a camshaft fault in the BMW 730 cause unstable idle speed?

[StGenesis]

BMW 730 camshaft fault causes unstable idle speed due to severe wear between the bearing bush and journal on the intake camshaft, resulting in scoring phenomena. Solution: The adjustable camshaft control device improves torque in the low and medium speed ranges while setting reasonable valve timing phases for idle and maximum power. By reducing valve overlap, it minimizes residual gas volume during idle conditions. Camshaft function: Controls the opening and closing actions of valves. Although in four-stroke engines the camshaft rotates at half the crankshaft speed (in two-stroke engines they rotate at the same speed), it typically operates at high rotational speeds and must withstand significant torque.