I suggest that you should check the FD for leaks in the bottom to the airflow housing. Push the air meter plate and see if the inner wall is moist and if there is any fuel inside the housing .
In my opinion the FD leaks because there is excessive pressure in the fuel line. It happens when there is dirt and water in it. To stop the FD from leaking I do the following:
1 Tap on the fuel pressure regulator and restart the car. If the problem persists add an injector cleaner and drive some 300-400 kms.
2 Remove the injectors and using the medical injector (with no needle) force some injector cleaner into the injector (picture). This will clean it from dirt and you will see how the spray pattern improves. Use rubber gloves and take caution because liquid is flammable and bad to inhale.
3. To clean the injectors from water use the tire inflators pressure to let high pressure air through the injector. In my case there was lots of water in injectors.
Doing the steps above stops my cars FD from leaking.
1989 230E, 8v, 166.000 km, updated to 94/95 trunk & hood
2002 Daewoo Nexia 50.000 km
1987 VW Jetta GLE 16V, Recaro seats
1982 Volvo 240 DL (lovely car!)
and few more american cars.