Cant get the idle correct

[flipsgonetopless]

Okay, my patience is running thin. My idle started running really rough and I cant get it running smooth again. I've already bought $70.00 worth of vacume hoses from the dealer (all original BMW) and still idling rough, what I mean by rough is the car is running on low RPM's and sputtering like it needs a tune up. On that note, I replaced the spark plugs and one bad ignition (#3 to be exact) and its still running like its miss-firing. I dont know what else to do anymore, now I am begining to think its the crank sensor. help me out here and give me some pointers to get my ride running smooth like before.
Thank you all in advance.

Flip...

[Starmavin]

If it was your crank sensor it wouldn't run. If it runs good otherwise (accelerating and driving), test your throttle position switch.

[gotKRAUT]

x2 check the throttle switch....that was my culprit

[flipsgonetopless]

Yesterday when I got home, I unplugged the sensor and the idle stabalized a bit. It may be my sensor but how can I check it, how can I test it to be sure that this is whats causing my issue?
do I need a ometer and check continuity or what do I do? I need to get this going because its very frustrating to be at a red light and the car is idling crappy.

[Starmavin]

With the engine of check for continuity between the center and the outer ones. Only one side should show continuity at idle then check the other at wide open throttle. Then only that side will show continuity, never both.