Are you getting lean engine codes such as P0171 to P0175? Is your car over 100,000 miles or 15 years old? The PCV hoses become brittle and deteriorate over time. This video shows how to cheaply replace the crankcase ventilation or breather hoses on a 2000 Mercedes S500/S430 but the procedure applies to other M112 (W210) and M113 engine models. As a bonus, the video also contains footage on how to clean the Mass Air Flow (MAF) sensor and Throttle Body on a W220 model.