I had the idea that the EGR valve might be a good place to inject the steam. Then i started researching my intake manifold.
Here is a picture of it.
The pipe with the garden hose attached is the EGR hose.
The intake manifold looks like a fancy one.
![](http://www.benzworld.org/forums/attachments/w163-m-class/938417d1399746791-intake-changeover-valve-questions-vanes.jpg)
(Not my pictures)
It does not look like the egr gas reaches all of the cylinders equally.