Greetings once again,
An ongoing stalling problem.
The car has already had a tune up, timing is set to 5bdc, new spak plugs and wires. Changed fuel filter and all fluids.

When I am driving in the parking lot at about 1500rpms and let go of the gas pedal the car occasionally stalls. Also if nuetral you rev the car up to 1500rpms and hold it there for a few seconds and then drop it, the car will stall or try to stall.

As far as I know the Idle Control Valve has been replaced, but the vacuum line coming out of it (the black tube that's connected to it) wasn't connected to anything, so I connected it to the intake manifold (??). In addition, there is also a red sensor 3-4 inches away from the idle solenoid screwed into the intake manifold with two port for vacuum lines, one of them is is not connected. The mechanic also told me that I have problems with the vacuum lines, but I don't have a diagram because my cd's from mercedes are on backorder.

Let me know if I picture would help.

Any help or drawings are appreciated.

Any ideas would be appreciated.