1991 E34 525i M50 uneven idle

[Linuxguru]

Hi,

My tireless companion was last week struck with sudden idle sickness and is not willing to run properly when applying throttle.

I found a youtube video which demonstrates the exact same idle noise as my car produce as far as I can judge:

http://www.youtube.com/watch?v=WVbNG8t-cW0

The following have been observed/performed:

- Idle rev is around 500rpm and constantly struggling. Normally my car idles at 650-700rpm. There is almost no pulsating on the tacometer, although the sound in the video indicate that the engine is pulsating.
- By applying throttle I can get it up to 2k-3k rpm, but by holding the throttle this way the engine will choke itself back to idle after 2-3 seconds.
- By disconnecting the MAF cable, the car runs almost as normal. I can sometime hear the pulsating sound slightly, but the car appears to go normally even when holding throttle over a period of time.
- Disconneced and cleaned MAF, no change. When replugging the MAF, the car goes back to struggling on idle around 500rpm. To me this indicate that the MAF is actually producing a signal, and is most likely not faulty.
- Sprayed all vacuum hoses with start spray + gone over vacuum tubes. Difficult to reach in under manifold, but no change in rev was experienced during this.
- ICV changed about 4-5 years ago, together with inlet and vacuum hoses. When ICV was faulty, the rev was constantly hunting. I don't experience this now, so I dont suspect the ICV.

- What to check next? Can faulty ECT sensor cause this?
- Can I disconnect the MAF cable and drive to mechanic without destroying something?

Thanks in advance for suggestions.