As Cars shun Vacuum controls the modern trend is to use Sensors and electric motors. With our two C Class CGI Mercedes I could not find a vacuum take off point to introduce a cleaner into the Manifold to clean the intake valves. As only Air now passes them with direction injection there is no longer fuel passing to keep them clean. Then I remembered that the MAP Sensor is plugged into the inlet Manifold, buried under the Air filter box and the ECU. So nothing ventured nothing gained , I removed it and was able to spray in a can of special cleaning fluid. Same as Subaru use in their Boxer Engines. Also Porsche Boxer Engines. . The engine still ran with the Sensor out.