Bucking while in between on gas pedal or fully off pedal

[VW+bimmer=bliss]

Just a note on the hose I'm talking about. When I was doing the head gasket on my 88 735i, I figured I would replace the original hardened hose with a nice new plyable one. I did so but the new hose (aftermarket) was too soft and would collapse on itself with the vac from the motor. This ended up creating a tiny pinhole leak in the hose and gave me fits for a 4,000 mile trip. I didn't find the problem until I got home. I swapped back the old hose and it has been fine since.

I had that problem with a new hose I put on. Fixed it by putting these small plastic rings inside the bendy portions of the hose, they hold the hose in the intended shape.
when it would get vacuumed flat at idle, it would make a really annoying and quite audible whistle.

[revse28]

Hey guys,
Was looking through some of my old posts and realized I never posted fix on this problem. Changed out speed and reference sensors, fixed.
But, since this problem arose in 2013 I have changed the engine as well in 2014! So all kinds of goodies were replaced with new parts. She is running great. Went from 274k on engine to 115k. New seals, gaskets, and all the other good things that one can do to a motor without total overhaul.