I Need Some Expert Help

I HAVE A 82 320i, CAR WAS RUNNING FINE AND THEN ONE MORNING STARTED IT UP AND IT ACTED AS THOUGH IT WAS RUNNING ON 2 OR 3 CLYN, AFTER IT WARMED UP THE PROBLEM WENT AWAY AND RAN NORMAL, THIS OCCURRED FOR TWO DAYS. NOW THE PROBLEM IS FULL TIME DOESNT GO AWAY. IVE CHECKED ALL THE OBVIOUS, PLUGS, WIRES, CAP ALL SEEMS OK. I AM TRYING TO AVOID TAKING TO THE SHOP CAN SOMEONE GIVE ME AN IDEA OF WHAT THIS PROBLEM MY BE???

Not sure if your bmw has this items but check the Idle Position sensor and the Idle and Air control module.

OK WELL THIS WAS A FIRST FOR ME, IN BACK CHECKING MY PREVIOUS WORK I FOUND THAT THE #4 CYLN WASNT FIRING, EVEN THOUGH I HAD JUST PUT NEW PLUGS AND WIRES IN. FURTHER INSPECTION I FOUND THAT THE NEW BOSH PLUG WAS BROKEN INSIDE ITSELF. AND EVEN FURTHER I CHECKED THE OLD PLUG AND IT WAS BROKE INSIDE. WHAT ARE THE ODDS OF THAT???
MY NEXT ? IS COULD SOMETHING BE CAUSING THIS TO HAPPEN OR IS IT JUST A COINSIDENSE???