<E28> Stumbling engine / running rich?

[khensley@xxxxxxxxxxxxxxxx]

I hope this is not a repeat for you all.  I tried submitting this 
earlier, but I think I messed up the address.

OK - my 1985 535i suffered from an erratic idle a couple of weeks ago 
- - and it quit doing that.

NOW, it has come back with a vengeance!  The car won't idle unless 
I'm holding the throttle.  Once I'm on the throttle, everything is 
fine.  Even that brief moment off the throttle while changing gears 
the engine stumbles.

Back at idle, if I don't keep my foot on the throttle, and I find 
myself fighting a dying engine, I get puffs of black smoke.

Is it the idle control valve?  Throttle switch?  Something else?  
Vacuum lines are fine.

Private replies are fine.

...Kim
BMW CCA #16216

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