Yes they are notorious for leeks,when aged,they get hard and no longer keep a good seal. You may benefit from looking at a post I did on intake vacuum leeks,I rebuilt my wifes 420sel intake,replaced all of the rubber,including the plenum chamber,and injector seals as well as the injector cups, I got a used icv on line in parts for sale.If any thing the car idles to low now,but I also did some resetting of the EHA, and the POT. needed to be replaced. the mileage jumped up by 1.5 and the power is much better too. look up jim16671836,he may stll have a used one if not do the parts post for a used one.JNT