1995 850 t5 auto misfire?

I'd start by checking your ignition leads (or coils if you car runs coils). You can actually get a HT lead tester kit for a few quid, plug it onto the HT leads and then run the engine and it will show signs of any malfunction within the leads. It may be down to issues with a camshaft/crankshaft sensor (BMWs show similar signs after being thrashed and usually its the camshaft sensors that need attention).

...had a similar problem myself, last week - turned out the dizzy and rotor arm were deteriorating and the HT leads corroding.....got the plugs changed at the same time. this has solved the problem - sounds like yours may be just about the same!

a stage 0 tune up could be on order followed by an inspection of the inlet manifold/pcv pipe if yours is phase 2... cheers jod