Was this problem ever resolved? My 94 530i e34 with 170,000km has pretty much the same symptoms with two one additional ones. Very high fuel consumption 18-20 l/100km (city) 12 l/100km (highway) and the car really stinks. It's kind of a sweet bitumen smell not really sulfurous though.
Before the problem occurred a few years ago the consumption was more like 15 l/100km (city) and 7-9 l/100km (highway)
I spent $2k on the engine as per below, but the problem was not fixed. It improved for a few days and gradually got worse over weeks. Now it is terrible. If I were to sell the car nobody would go near it...
New spark plugs
Compression test (ok)
New (Bosch reco) injectors
New engine mounts
New PCV (BMW part)
New induction hose
I have checked and cleaned the ICV and checked all induction hose clamps etc which did not help.