BMW Z4 throttle valve spring test failure and unstable idle at 1100 RPMs on BMW Z4

Some BMW Z4 owners report experiencing a throttle valve spring test failure, indicated by error code P1634, which can lead to an unstable idle at 1100 RPMs. This issue may arise during the throttle valve's adaptation phase, causing the engine to idle erratically and potentially stall. Additionally, some owners notice that the engine may enter an ENGINE FAILSAFE PROGRAM when this fault occurs. To address these problems, some owners find that cleaning the throttle body can help, while others attempt to reset the system by switching the ignition on and off for a designated period. However, if these troubleshooting steps do not resolve the issue, it is recommended that owners seek assistance from a professional technician, as the failure of valves or their sensors may require expert diagnosis and repair.