toomany MBZ, about the vac lines in picture#3:
- car is a 4 door sedan, not coupe
- I don't see any other 1-into-2 yellow check valves, other than the one that is disconnected
- From the disconnected yellow valve there are two yellow vac lines that go to a connector at the firewall. Looks like 5 or 6 vac lines all connect here and go through the firewall. It's pretty dirty in there, but it looks like there may be one unconnected nipple in the middle of that connector. Hard to tell for sure though until I clean it up, and I don't see any stray lines nearby that look like they should go there.