1987 BMW 325

It will possibly require replacement of the idle control valve and idle control unit and checking the throttle position switch. The engine in an ETA car is 2.7 liters.

I forgot to say that this problem only started after replacing the crank sensor - or pulse generator as BMW calls it. I replaced the original crank sensor with an after-market sensor. The lead on the after-market sensor was shorter than the original, so re-routing the lead was necessary. I then replaced that one with a BMW sensor which had the correct length lead. Still the surge problem. Engine idled fine before changing the original sensor - has had problem ever since. The timing of the problem with the changing of the sensor seems suspect to me - but it also could just be a coincidence. Thank you again for your help.
Jeff

What was the reason for replacing a good crank sensor? Also what are the last 7 characters of the VIN?

The original crank sensor went bad - no signal. That's why I replaced it. The surge problem started after I installed the after-market sensor with the short lead. That's why I replaced the after-market with a BMW part - I thought maybe the after-market one wasn't exactly right and might be causing the surge problem. But the surge problem was still present after I installed the BMW part.The last seven of the VIN are: 8831325. Thank you.

Jeff

Alright, the issue here could well be a sticky idle control valve as the I motors have the idle control integrated into the engine management. Try cleaning the ICV and see if it helps.