>>Anyone??

The snippet posted ealier in the thread about X/O and 3/6 were results obtained from my 95 E300D. I checked their operation because I wasn't sure if someone before had messed up the wiring and piping.

These manifolds work a little bit like organ pipes - the long pipes make the low notes, and the manifolds should be long when the engine is running slowly - i.e., the air is pulsing at low frequency.

The valve in the crossover pipe should be closed at low engine speeds, so the two pipes remain independent - but, this should be the first valve to open.

The valve in the base of the manifold, which I called 3/6 should, again, be closed at low speed, so the manifolds remain long and independent, but, open at high speed, so the engine sees a very short manifold.

By your description, something seems to be plumbed in backwards.