1985 BMW 325E, stalls out of blue...why?

[matinct]

I've got a 1985 BMW 325E that's been garaged, and has 100,000 miles on it. It drives for 20 minutes beautifully, and stalls out of the blue. I can turn the key off, and it will start right away. It has been to (4) mechanics. When it stalls, rpms go from 4,000 to 0 with no sputtering. Fuel filters have been replaced, fuel pumps have been replaced. Alternator is new. Battery new. I believe it to be electrical as I have just noticed, my low beams do not go on. There are (4) bulbs, (2) for high (2) for low. When the high beams are on, all (4) bulbs light. Nothing in the low beam position. Any thoughts as to where or what is going on here? There was a car alarm installed that was removed by the previous owner, could there still be a kill switch somewhere? I'm fishing for any advice possible.

[e30m3]

Hi. It sounds like you have a tricky one. Does the car cut out after 20 minutes all the time ? ie. whether its being driven or just sitting idling ? Have you checked your error codes ? I have attached the url to a page that may help you decipher what the car has to say (if anything) go to http://www.unofficialbmw.com/repair_faqs/motronic.html for more info.

To be honest with you, I don't think the root cause is electrical. I think that the car's ecu is interpreting a physical sensor or something and shutting the car down. When you restart, its resetting and trying again.

I'd be interested to see what you find. Otherwise you may have to move closer to work (about 19 minutes drive should do it !)