Hi. If you look at the pix I posted earlier, you can see a couple of the fuel injectors just above the valve cover.
The injectors are held between the fuel rail (that "U" shaped tube) and the intake manifold.
The top and bottom each injector has an "O"-ring to seal it and prevent leaks.
You'll have to replace the seals and make sure the mating recesses for the injectors are clean.
Make sure everything is clean when you reassemble.

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KenP

1996 S500 W140 Coupe