Intermittent stalling on 535i. Motronic? (archive)

My '86 535 just developed an intermittent stall (every 2 hours or so). Can anyone offer some insight? Here are two typical scenarios, followed by some additional diagnostic info:

-I'm coasting down a hill. The engine dies, and the idiot lights turn on. I shift to 5th gear, release the clutch pedal, and it restarts instantly.

-I'm driving normally. The car suddenly "engine brakes." I wait a few seconds for it to restart, but it never does. I hit the clutch pedal, the engine dies, the idiot lights turn on, I release the clutch pedal, and it restarts instantly.

Apparently the engine has to officially stop before it will restart.

Here is some additional diagnostic info:

When the engine dies with the transmission in gear, the tachometer continues to show the rpms. With a traditional tach, that would mean there was still spark, but I don't know if the e28 tach works off the coil.

When the engine dies with the transmission in gear, the fuel economy gauge registers maximum economy, even if I (or the cruise control) floor the accelerator. This tells me that the Motronic unit has decided not to actuate the fuel injectors, as opposed to the problem being a faulty fuel pump or pump relay.

I've noticed that turning on various lights causes the temp. gauge to flicker a little, typically causing it to increase its reading. Sometimes it flickers for no apparent reason. The fuel gauge does not flicker. I'm guessing this is a ground problem. Could this be related to the stalling problem?

The car normally runs well, and idles steadily at 700 rpm.

Thanks in advance.

Follow Ups:

URL link to archives, re-solder ECU connections gale 00:09 11/19/2000 (2)
- Re: Resolder transister- Connections are good. RonW 22:14 11/19/2000 (0)
- Re: Symptoms don't match RonW 11:17 11/19/2000 (0)

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