Code 1264 !
My '90 E30 convertible started running rough - stalling a bit - about six months ago. She has been garaged most of the time since.
Yesterday, I reset the OBD codes and ran the car. Idle had surged when the problem occured six months ago, but is now smooth. After warm up I took the car out on the road and stomped the gas pretty hard. The engine stalled, then caught itself, and operation seemed normal from then on out. I drove around for an hour yesterday, reset the code again and drove some more. The check engine light comes on as soon as you start to press down on the gas pedal.
The code I get is 1264 - O2 sensor heating element. Does this mean the sensor is bad, or could it be the wiring that connected to the sensor. That looks pretty bad to me. There is also a relay over on the RH side of the engine compartment near the radiator fill container, that relay tested fine for resistance.
I'd really like to get this problem solved!! I assume that the car will likely suffer in terms of gas mileage, and that I might foul up the plugs running without the O2 working properly.