'89 Saab Engine dies while driving

My 1985 Saab 900 turbo has been dying while being driven. Suddenly, and usually while the car is relatively hot and in traffic, the engine will die while driving. Usually it will die when at a light stopped but not always. This has never happened before the last week or so, but the car has always had trouble with cold starts and will die while idling when the ignition is first turned. This hasn’t been diagnosed. At times a lot of smoke will come from the exhaust, and this has not had a trigger (too much oil, hard driving, etc) but the car did pass smog in California (the strictest state!). Just now, a light I’ve never seen (and I’ve had 2 80’s Saabs) came on the dash which said EXH, which I read could be regarding the o2 sensor? Just trying to give ya all the facts! Pleeeease let me know if you have guesses as to what can be the problem. I’d really appreciate it.

Your car has CIS fuel injection and these systems can be problematic. The cold start issues, smoke from the exhaust, etc can all be signs of CIS problems.

The usual suspect is the control pressure regulator or a vacuum leak. Getting into CIS diagnosis requires a specialized fuel pressure tester, pressure chart, and a vague knowledge of how it all works.
If you cannot do this you may have to turn to a Euro shop. If there is no SAAB facility someone who is familiar with older VWs, BMWs, or Benzes should be able to run the tests.

As to the EXH light, that is a service minder lamp that illuminates ever so often. To turn that off the left speaker grille has to be removed and a reset button (located near the small speedometer cable like fitting) on the instrument cluster has to be pushed. It’s not difficult to do; just awkward to see and feel around in there.

I’ll dig around and see if I can find a pic of that reset button for you.

Here’s a previous discussion on a similar problem:

This one wasn’t a turbo, but a partial solution was a new fuel pump.

(Also, '89 or '85? Please correct this discrepancy.)

True enough; the 85 and 89 are completely different. I’m assuming 85 because I think the EXH light was eliminated after the 1985 model year; or possibly 86.